Read the real reason first
Anti-detect browsers show a generic message and hide the gateway's answer. Getting that answer takes a minute:
- Paste the proxy into the TrueProxies proxy checker, or
- Run it with curl over HTTP on port 8080 and look for the
X-Proxy-Reasonheader (the 407 body carries the same text):
curl -v -x "http://YOUR_HOST:8080" \
-U "YOUR_USERNAME-country-us-session-shopus01:YOUR_PASSWORD" \
https://example.com -o /dev/nullUse HTTP even if the profile runs on SOCKS5, because SOCKS5 fails at the login step with no reason text. A bare 407 with no reason at all means the gateway rate-limited you after repeated failed attempts: wait 60 seconds before checking again.
TrueProxies gateway reasons and what to do
| Reason (verbatim) | What to do |
|---|---|
| "Username not recognised. Check the username on your service page." | Copy the base username again from the dashboard |
| "Username not recognised, or the service it belongs to has ended. Check your service page." | Confirm the service is active, then recopy the username |
| "Wrong proxy password. Check the credentials on your service page." | Recopy the password. Targeting options never change it |
| "No credentials sent, and this address is not on the service's trusted IP list." | Add your IP to the trusted IP list, or send a username and password |
| "The targeting options in your username are not valid for this service. Check spelling, and do not repeat an option." | Fix the option: country-us, not country-usa; gb for the UK; use city with country; lifetime only with session; city, region, ASN and lifetime need a Traffic pack |
| "This service has used its traffic allowance. Add traffic to continue." | Add traffic or buy a larger Traffic pack |
| "This service has reached its expiry date. Renew it to continue." | Renew the service |
| "This service is not currently serving." | Check the service's status on its service page, or contact support |
| "This service is suspended. Contact support to resolve it." | Contact support |
| "Your trial has closed. Buy a paid plan to continue." | The free trial lasts one hour; move to a Traffic pack |
| "This service is temporarily unavailable. Try again in a moment." | Retry shortly |
| "Too many new connections per second for this service's limit." | Check long lists in smaller batches |
| "This service is at its maximum number of open connections." | Close idle profiles or tunnels |
| "The proxy is at capacity right now. Try again in a moment." | Retry shortly |
| 403 Forbidden | The site is a private, reserved or blocked destination |
| 502 Bad Gateway | A Datacenter IPv6 exit met a site with no IPv6 address |
| 503 Service Unavailable | A closed destination port, no available exit, or a site that refused or timed out |
| SOCKS5 0x02 or 0x03 | After login: connection not allowed by ruleset (0x02), network unreachable (0x03) |
Full reference: proxy checker error codes and the TrueProxies errors docs.
Errors by browser
Each table lists the messages people search for most. Each browser's guide has the full table.
AdsPower
| On screen | Usual cause | Fix |
|---|---|---|
| "Connection test failed!" (the same text for every failed check) | The gateway refused the login or the targeting options, the traffic ran out, or the type doesn't match the port | Read the reason; pair HTTP with 8080 and SOCKS5 with 1080 |
| Red "Inactive and connection test failed" in a bulk check | Too many new connections at once, or a rate limit after failures | Check in smaller batches; wait 60 seconds after failures |
| Gray "Waiting for check" | Not an error: the proxy hasn't been checked yet | Select it and click Check proxy |
| "Proxy failure" when a profile opens | The profile's proxy connection failed: changed credentials, used-up traffic, or a VPN or proxy app on your computer | Run Check proxy, quit VPN and proxy apps, try another network |
| "Abnormal" in Network Diagnostics | Your clock is more than 5 minutes off, or a system proxy or leftover HTTP_PROXY / HTTPS_PROXY variable is set | Fix the computer settings (see below) |
Full table: AdsPower proxy errors and fixes.
Dolphin Anty
| On screen | Usual cause | Fix |
|---|---|---|
| "Failed to establish a proxy connection. Check proxy operation, if possible, with an external VPN or other access point to rule out a GEO connection conflict." | The check couldn't connect: credentials, options, an ended plan or trial, or a network blocking the gateway | Read the reason; if the proxy passes in the checker, try another network |
| "Error checking connection to proxy" | The proxy failed its check, so Dolphin won't start the profile | Fix the cause, then Start again |
| A red Error status with no text after Check connection | In our test: a wrong password, a misspelled option (country-usa) or SOCKS5 on port 8080 | Read the reason in the proxy checker |
| "ValidationError: 'port' length must be less than or equal to 5 characters long" | An unsupported layout such as login:password:host:port | Use host:port:login:password or login:password@host:port, with no spaces |
| "You have reached the proxy limit of your current plan" | The Free plan's proxy cap | Delete unused proxies or upgrade |
| "ETIMEDOUT", "Error: socket hang up", "ECONNRESET" | Network or proxy trouble while a profile starts or closes | Test in the checker, then switch networks |
Full table: Dolphin Anty proxy errors and fixes.
GoLogin
| On screen | Usual cause | Fix |
|---|---|---|
| "Proxy error. Proxy connection timed out", "Proxy error. Proxy server doesn't respond" or "Check timeout exceeded" | GoLogin couldn't reach the proxy | Check the host and port; try another network |
| "Proxy error. Response code 407 (Proxy Authentication Required)" | The gateway refused the login or the options | Read the reason in the checker |
| "Proxy login or password error" (hover the red Error state) | The gateway refused the username or password | Copy the credentials again from your dashboard |
| "Received invalid Socks5 initial handshake (invalid socks version)" | SOCKS5 pointed at a non-SOCKS port | Use port 1080 for SOCKS5 |
| "Socks5 proxy rejected connection:NotAllowed" | The gateway refused that destination after login | Open the same site over HTTP on 8080 to read the reason |
| "The proxy is functional but not working on your device or network" | GoLogin's server check passed, but your network blocks the proxy | Try another network; check the firewall |
Full table: GoLogin proxy errors and fixes.
Octo Browser
| On screen | Usual cause | Fix |
|---|---|---|
| "Failed to get proxy data due to a connection error" | The profile's proxy, or your internet connection | Test the proxy in the checker; if it passes, try another network and set Client server to Auto |
| "Proxy connection failed" | A proxy or connection problem, sometimes antivirus blocking Octo's components | Read the reason; add Octo to antivirus exclusions |
| Red Unavailable after Check proxy | The check failed or ran past Octo's 5-second default timeout | Read the reason, fix it, check again |
| "Cannot change proxy IP. Please try later" | The IP change URL is wrong or blocked | Clear that field and change the session ID instead |
MoreLogin
| On screen | Usual cause | Fix |
|---|---|---|
| "Detection Failed" | The check failed: login, options, used-up traffic, or type and port | Read the reason in the checker |
| "Detection Failed" after Batch Add | Lines without a type were saved as SOCKS5 but point at 8080 or 8443 | Add http:// to those lines, or use port 1080 |
| Wrong city or timezone after a pass | The IP Query Channel placed the IP differently | Switch the channel and check again |
| A cloud phone fails Network Detection | The phone needs a working SOCKS5 proxy | Use SOCKS5 on 1080 with username and password |
Multilogin
| On screen | Usual cause | Fix |
|---|---|---|
| "Proxy check failed" | A host typo, the protocol on the wrong port, a refused login, used-up traffic, or a local VPN, antivirus or firewall | Read the reason; match protocol to port; check again |
| "Wrong proxy data" | A malformed string | Use IP:port:login:password with no spaces or scheme |
| "Profile failed to start" | A failing proxy, among other causes | Check the proxy first |
| "The proxy server is refusing connections" (Firefox-based core) | Wrong port or protocol, or a local firewall | Match protocol to port |
Incogniton
| On screen | Usual cause | Fix |
|---|---|---|
| "No connection" (proxy status) | Incogniton's check couldn't get through the proxy | Check type vs port, the port in the address, the auth method and the IP version |
| Wrong location after Check | Incogniton's location lookup disagrees with the IP | Switch Proxy provider to Backup provider |
| Red bolt in Proxy Ping | Incogniton rates the latency "Bad" | Pick an exit nearer the target site, or a new session ID |
Kameleo, DICloak, BitBrowser, ixBrowser and GeeLark
These tools document their test buttons rather than message strings: Test Proxy in Kameleo (since 5.2.1 it explains failures in plain language with a copyable report), Checking proxy in DICloak, Proxy Detection in BitBrowser, and proxy detection for GeeLark cloud phones. When any of them reports that a proxy or proxy connection failed, use the same order: read the gateway's reason over HTTP, confirm the type and port pair (HTTP on 8080, SOCKS5 on 1080), then test from a second network. Kameleo's docs treat HTTP and HTTPS as one type, and ixBrowser's batch lines default to HTTP, so point those at 8080.
Chromium error codes inside a profile
Most anti-detect browsers run on Chromium, so a failing profile often shows Chrome's own error page.
| Code | What it means | What to do |
|---|---|---|
ERR_PROXY_CONNECTION_FAILED | The browser couldn't reach the proxy host or port | Recopy the host; check the port; pause local VPN or firewall tools |
ERR_TUNNEL_CONNECTION_FAILED | The proxy refused to open a tunnel to the site | Read the status: a 407 reason, 403 (blocked destination), 502 (IPv6 exit, IPv4-only site) or 503 (no exit, closed port, refused) |
ERR_SOCKS_CONNECTION_FAILED | The SOCKS5 connection or login failed | Test the same login over HTTP on 8080 |
ERR_CONNECTION_RESET, ERR_CONNECTION_CLOSED, ERR_CONNECTION_TIMED_OUT | The connection dropped, for example when a sticky exit went offline | Check the proxy again; if the IP changed, restart the profile |
Firefox-based profiles (one of Multilogin's cores) show "The proxy server is refusing connections" for a wrong port or protocol, and "Unable to find the proxy server" for a host typo.
When the problem is your computer, not the proxy
If the proxy passes in the checker but fails in the browser, look at the machine and network:
- Clock. AdsPower flags a system clock more than 5 minutes off. Turn on automatic time.
- System proxy and environment variables. A system-wide proxy, or leftover
HTTP_PROXYandHTTPS_PROXYvariables, can sit between the browser and the gateway. Remove them. - VPN and proxy apps. Quit them while testing. AdsPower lists them as a cause of "Proxy failure".
- Antivirus and firewall. GoLogin's "EACCESS" error and Octo's "Proxy connection failed" can both come from security software blocking the browser's components. Add an exception.
- The network itself. Some office and public networks block proxy ports. GoLogin says so outright: "The proxy is functional but not working on your device or network". Test from a phone hotspot.
- Extensions. A VPN or proxy extension inside a profile can override its proxy, so your own IP shows instead.
When the check passes but the location looks wrong
Browsers use different IP lookup databases, and they disagree, especially on cities. If the profile's city or timezone doesn't match what you targeted:
- Open the IP leak test inside the profile to see where the exit really is.
- Switch the browser's lookup service if it has one: AdsPower's IP checker, MoreLogin's IP Query Channel, Incogniton's Backup provider, DICloak's IP check channel.
- Otherwise set the timezone, language and geolocation by hand.
Octo Browser shows a question mark instead of a flag when its lookup can't place the IP at all.
When the IP changes in the middle of a session
Sticky sessions hold an IP for up to 24 hours on a best-effort basis. If the residential exit goes offline, the session gets a new IP, and browsers react: MoreLogin can warn on an IP change, and Chromium may show ERR_CONNECTION_RESET until the profile reconnects.
Keep the same session ID, set lifetime-86400, and check the proxy again before you continue. A profile that must keep one IP for weeks needs a static ISP proxy, which TrueProxies doesn't offer.
IPv6 exits and browser checks
A Datacenter IPv6 exit reaches only sites that have an IPv6 address; anything else returns 502. Many browsers check a proxy and look up its location through services that may not answer over IPv6, so the browser's check can fail even when your target site loads. Each guide reports what happened in our test. Check targets first with the IPv6 test, and remember the reverse case: Traffic pack exits are IPv4 and can't reach IPv6-only sites.
Anti-detect browser proxy error FAQ
Why does my anti-detect browser say the proxy failed when it works elsewhere?
The browser's check runs from your computer to its own lookup service, so a blocked port, a security app, a wrong type and port pair, or a lookup service that doesn't answer over IPv6 can fail it while the proxy itself works. Read the gateway's reason in the proxy checker, then test the browser from a second network.
What does a 407 error mean in an anti-detect browser?
407 Proxy Authentication Required means the gateway refused the request before it left for the site. With TrueProxies the 407 carries a reason: a wrong password, an unknown username, invalid targeting options, used-up traffic, an expired service or a closed trial. A bare 407 with no reason means too many failed attempts; wait 60 seconds.
Why do SOCKS5 proxy errors show no reason?
SOCKS5 has no field for an error message at the login step, so a refused login just fails. The gateway can only return short codes after login, such as 0x02 (not allowed) and 0x03 (network unreachable). Test the same username and password over HTTP on port 8080 to read the full reason, then switch back.
Why does my browser profile's IP change during a session?
Residential sticky sessions are best effort: if the home connection behind the exit goes offline, the session gets a new IP. The session also ends when its lifetime runs out. Keep the session ID the same, set the lifetime as long as the profile needs (up to 24 hours), and re-check the proxy after any reconnect.
Can a Datacenter IPv6 proxy fail an anti-detect browser's proxy check?
Yes. The exit reaches IPv6 sites only, and the services a browser uses to check a proxy or locate its IP may not answer over IPv6. Then the check fails even though IPv6 sites load. Our guides report each browser's result; if yours fails, use a Traffic pack for that profile or set its location by hand.
How do I stop errors when checking hundreds of proxies at once?
Bulk checks open many new connections in a burst, which can trip "Too many new connections per second for this service's limit." Check in smaller batches, and if a batch fails, wait 60 seconds before the next one, since repeated failures also trigger a short rate limit.