If the servers are up but you can't connect, your ISP might be blocking the connection to the tool's backend. Try using a high-quality VPN and set your location to a different region (like the USA, Singapore, or Germany).
It sounds obvious, but the most common cause for the "Invalid Username or Password" error is a simple typo or an expired account. unlock tool invalid username or password or server timeout
Sometimes the servers are down for maintenance or are overloaded during a major update (like a new Samsung or Xiaomi security patch release). Check the official Unlock Tool Telegram channel or Facebook group for "Server Down" announcements. If the servers are up but you can't