Here are some possible causes of login errors in MT4. Please try resolving them before logging in again.

When copying and pasting the account info, make sure you're not including any unnecessary spaces. When entering the password, make sure CapsLock is disabled. Watch out for identical characters such as "1", "I" (capital i), and "l" (lower-case L) and try again.

Check your server settings once again. Most FX brokers own multiple servers (Demo, real account, by user, etc.). Therefore, if you choose the wrong server, you won't be able to log in. Check the specified server linked to your account and try again.

If your internet connection is out/unstable or the server is busy/shut down, you'll run into errors when trying to log in. Click on the connection status box on the bottom right of MT5 to check the server connection status. If the icon is red or gray, that means you're not connected to the server. Please try again later or contact your forex broker for further assistance.

If your MT5 is outdated or you're using MT5 apps provided by other forex brokers, you may run into server connection errors.

Related article: Check your MT4/MT5 version

Some forex brokers won't activate your account until you make a deposit while some will deactivate your account if it hasn't been used in a while. Both cases will cause an error when trying to log in. Furthermore, if you're using a demo account, check the expiration date. If your demo account is expired, you won't be able to log in. If you wish to reactivate your account, please contact your broker for support.

To login to MT5, you need the MT5 account information. You can't use the MT4 account information.