How to fix MetaTrader sync that doesn't send trades

If trades don't arrive from MT4 or MT5, the Experts tab shows the reason. These are the usual causes and their fixes.

Steps

In MetaTrader open the Toolbox → Experts tab and read the latest NovaTradeSync message.
“WebRequest failed”: go to Tools → Options → Expert Advisors, tick “Allow WebRequest for listed URL” and add the ServerUrl address from Accounts.
“Paste your API key”: open the Expert Advisor inputs and paste the key in ApiKey.
“This API key belongs to a different MT5 account”: use the key of the matching account in Accounts.
Or open the account page and click Unlink. The next MT5 account that syncs with that key is linked instead.
Check that the Algo Trading button is green.
For trades older than 30 days, raise HistoryDays in the inputs and attach the Expert Advisor again.

The account page shows “Linked to MT5” with the login number once a sync has linked the key.
Sending the same history again never duplicates trades.

Tell us what you were trying to do and what happened. A person replies by email, usually within one business day.