Proxies that only look dead
Wrong protocol, wrong output shape, missing credentials. The three settings that fail exactly like a broken address.
Proxies that look dead but are only formatted wrong
Before assuming an address is dead, rule this out. It takes ten seconds and it is the cause more often than a real fault.
Protocol. Leave it on HTTP unless your tool genuinely speaks SOCKS. Picking SOCKS5 in a tool that expects HTTP fails in exactly the same way a broken proxy does: no connection, no useful error.
Output shape. The dropdown above the proxy field switches between the common shapes:
| Host first | host:port:username:password |
| Credentials first | username:password@host:port |
| Full URL | http://username:password@host:port |
**Custom** takes the placeholders {host}, {port}, {username} and {password}, so you can build the exact line your bot expects instead of reformatting by hand.
Note: An HTTP 407 means the credentials did not arrive, not that the address is dead. Nine times out of ten the username and password were dropped by the tool rather than rejected by us.