How to find your MT5 server name
A wrong or mistyped server name is the most common reason an MT5 connection fails. The name is case-sensitive and must match exactly.
Where to find it
Your broker shows the server next to each MT5 account in its client area, and includes it in the email sent when the account was opened. It looks like Broker-MT5Real7 or Broker-MT5Trial15.
In the MetaTrader 5 app
If the account is already logged in on your phone or computer, the server appears in the account details (on the desktop app under File, then Login to Trade Account).
Demo and real accounts use different servers
Demo servers usually contain Trial or Demo in the name. A real account will not log in on a demo server and the reverse.
Still failing?
Check that you used the trading password, not the broker website password, and that the account is an MT5 account (MT4 accounts cannot log in to MT5).