Right-click the unlock tool → . Many tools need admin rights to establish a network connection properly.
Sometimes the error is a lie. Many unlock servers will return "Invalid username/password" if they detect something suspicious, even if your login is correct. This includes: unlock tool invalid username or password or server timeout
Older or beta versions of unlock tools often have broken authentication servers. Download the directly from the official source (not a random forum link). Right-click the unlock tool →
, the server was back online, and his login finally clicked through. Are you seeing this error with a specific software like Mi Unlock, SamKey, or a different utility? the server was back online