When a proxy is not working, nine times out of ten the cause is not the server but the client-side setup: login and port pasted into the wrong fields, your computer's IP missing from the whitelist, the wrong protocol selected. This article is a checklist for anyone who has bought a proxy and is now looking at a connection error, an endless loading spinner or a password prompt.
Work through the steps from top to bottom. Each one rules out a group of causes, so by the end of the list you will either have found the problem yourself or collected exactly the data support needs to fix it in one reply.
Step 1. Check the ip:port:login:pass format
Access details come in the ip:port:login:pass format, for example 185.12.34.56:8000:user123:Qw8rT2. The most common mistake is pasting the fields into the wrong boxes. Browser extensions and anti-detect browsers usually expect the order “host, port, username, password”, while some scrapers want login:pass@ip:port.
What to check:
- There is no trailing space at the end of the line after copying it from the dashboard or Telegram.
- The port is entered as a plain number, with no colon and no protocol prefix.
- The password contains no characters your software may interpret in its own way: @, :, #. If it does, change the password in the dashboard to a plain alphanumeric one.
- If you have several proxies, make sure you have not pasted the credentials from a different address.
A quick test from a Windows or Linux terminal: curl -x http://login:pass@ip:port https://api.ipify.org. If the command returns the proxy's IP, the credentials are correct and the problem is in the settings of one specific program.
Step 2. IP whitelist or username and password: which one is active
Most providers, ProxyFarm included, offer two ways to authenticate: by username and password or by a whitelist of IP addresses. If the whitelist is enabled in your dashboard and your external IP has changed (your home router reconnected, you moved to a different office, a VPN switched on), the proxy will stop responding or start asking for credentials.
How to check:
- Look up your current external address on the My IP page.
- Compare it with the address listed in the whitelist in your dashboard.
- If they differ, update the list or switch to username and password authentication. For dynamic home IPs the second option is more reliable.
A special case is mobile internet on a computer: the carrier changes your external IP every time you reconnect, which makes a whitelist practically useless.
Step 3. Protocol: HTTP(S) or SOCKS5
At ProxyFarm a single port accepts both HTTPS and SOCKS5, but many providers issue a separate port for each protocol. If your program is set to SOCKS5 while the port only serves HTTP, the connection will hang without an error or drop on a timeout.
Signs of a protocol mismatch:
- The page loads forever with no error message.
- Your scraper logs show Proxy CONNECT aborted or SOCKS handshake failed.
- Telegram or another messenger shows “Connecting…” and never reaches “Online”. Telegram only works over SOCKS5 and MTProto; it will not accept an HTTP proxy.
Switch the protocol in your client settings and run the test again. The differences are covered in detail on the SOCKS5 proxies and HTTPS proxies pages.
Step 4. Proxy and firewall check: is the port blocked
If the credentials and protocol are correct but there is still no connection, check whether your traffic reaches the proxy port at all. Corporate networks, antivirus suites and the built-in Windows firewall often block non-standard ports such as 8000 or anything in the 10000–65000 range.
From PowerShell: Test-NetConnection ip -Port port. On Linux and macOS: nc -zv ip port. A result of “TcpTestSucceeded: True” or “succeeded” means the port is reachable. If you see “False” or “timed out”:
- Temporarily disable your antivirus and firewall and repeat the test. If it works, add the program to the exceptions list.
- Try connecting from your phone over mobile data. If that works, the block is at the level of your network or ISP.
- Check whether a VPN is running: some VPN clients capture all traffic and do not let proxy connections through.
- If the port is closed from every network, contact support: the problem is most likely on the server side.
Step 5. Proxy server error codes: 407, 403, 502 and others
When the connection to the proxy is established but the site still does not open, the proxy server returns an HTTP code. That code pinpoints the cause.
| Code | What it means | What to do |
|---|---|---|
| 407 Proxy Authentication Required | The proxy is asking for authentication: the username and password were not sent or are wrong, or your IP is not on the whitelist | Check the credentials (steps 1 and 2) and make sure the program actually sends the username and password |
| 403 Forbidden | The proxy refused access: the plan has expired, the traffic limit on a residential plan is used up, or the target domain is blocked by the rules | Check the rental period and remaining traffic in the dashboard; ask support whether the domain is restricted |
| 502 Bad Gateway / 504 Gateway Timeout | The proxy could not reach the site: the site is down, the mobile device in the farm is rebooting, or an IP change is in progress | Wait 30–60 seconds and retry; check whether the site opens without the proxy |
| 429 Too Many Requests | The target site has rate-limited this IP | Slow down, rotate to a new IP, spread the load across several addresses |
| ERR_PROXY_CONNECTION_FAILED / ECONNREFUSED | No connection to the proxy: the port is closed or the address is wrong | Step 4: check the port and firewall |
| ERR_TUNNEL_CONNECTION_FAILED | The HTTPS tunnel through the proxy failed: wrong protocol or the proxy does not support CONNECT | Step 3: switch the protocol |
Code 407 sometimes appears even with correct credentials: Chrome cannot fill in proxy credentials by itself and shows a login dialog instead. This is normal: enter the details once or use an extension that stores them.
Step 6. The proxy works, but the site will not let you in
A separate situation: the connection is up, the IP resolves correctly, yet the target platform shows a captcha, asks you to confirm a phone number or says “access restricted”. This is not a proxy server error but the site reacting to the address's reputation or to a mismatch in your profile.
What to check:
- The IP's geolocation matches the time zone, browser language and account region. A Russian account on Avito, the country's largest classifieds site, logging in from a German IP will almost certainly trigger a check.
- The IP is not listed in spam databases. Run it through the proxy checker: the tool shows the Spamhaus and Firehol status, the country and the address type.
- The proxy type suits the task. Platforms such as Instagram and Avito treat datacenter IPv4 with far more suspicion than mobile or residential addresses.
- Dozens of accounts are not sitting on the same address at the same time, which is a real concern with shared packages.
If the IP turns out to be blacklisted or does not suit the platform, ProxyFarm replaces it free of charge within the first 24 hours after delivery. Request a replacement through the dashboard or Telegram support.
What to send to support if nothing helped
To get your issue resolved in the first reply, gather the data before you write. ProxyFarm support works 24/7, but without this information the first answer will be a list of follow-up questions.
- The proxy string (without the password: the engineer can see it in the system).
- Your external IP from the My IP page and the authentication method (whitelist or username).
- The program and protocol the proxy is configured in.
- The exact error text or the code from the table above.
- The output of the curl or Test-NetConnection command.
- When the error started and whether it reproduces from another network.
With this set of data, diagnosis on the provider side takes minutes: the engineer can see whether your requests reach the server, which code it returns and what state the farm device is in.
Related questions
The proxy asks for authentication even though the username and password are correct. Why?
Most often whitelist mode is enabled and your external IP has changed, so it no longer matches the list. The second possibility is that the program is not sending the credentials: Chrome, for example, shows a login dialog on every launch. Check the authentication method in the dashboard and switch to username and password if needed.
What does proxy server error 502 mean?
The proxy accepted your request but could not get a response from the site. Possible causes: the site is down, the mobile device is rotating its IP, or the channel is overloaded. Wait a minute and retry. If 502 persists for more than 5 minutes on every site, contact support.
How do I tell whether the problem is the proxy or my firewall?
Run Test-NetConnection ip -Port port in PowerShell. If the port is unreachable from your computer but reachable from your phone over mobile data, your network or antivirus is blocking it. If it is unreachable from everywhere, the problem is on the server side.
The proxy works, but the site shows a captcha and asks me to confirm a phone number. Is the proxy faulty?
No, technically the proxy is fine. The platform is reacting to the IP's reputation, a mismatch between the geolocation and the profile, or the address type. Check the IP against spam databases and make sure its region matches the account. If the address does not suit the platform, it will be replaced free of charge within the first 24 hours.