MT5 login failed / invalid account

Causes, most likely first

1. The wrong trade server was selected

By far the most common cause. Brokers run several servers and an account belongs to exactly one — "Broker-Server02" will refuse an account that lives on "Broker-Server04" with an error that reads like a bad password. The correct name is in the account opening email.

2. It is an MT4 account in an MT5 terminal

MT4 and MT5 accounts are separate and not interchangeable. An MT4 login will never authorise in MetaTrader 5 regardless of how correct the credentials are. See MT4 vs MT5.

3. The investor password is being used instead of the master

The investor password connects read-only, so it may appear to work while no trade can be placed. If login succeeds but trading is disabled, this is the first thing to check — see trade disabled.

4. The account is archived or inactive

Brokers archive demo accounts after a period of inactivity and close unfunded live ones. The terminal reports this identically to a credential failure. If the login worked previously and now does not, this is the likely reason.

Why this happens

The error message is unhelpful because MetaTrader cannot distinguish "wrong password" from "this account does not exist on this server". Both produce the same text, and the second is far more common.

Rather than retyping the password, search for the broker in the server list and try each of their servers in turn. It resolves most cases within a minute.