".. trying to set up my demo account to give signals .." - means that you want to provide the signal using your demo account, right?
If yes so, theoretically speaking - I can say about two possible reasons:
- you provided wrong investor password to connect your trading account to the signal system to create a signal https://www.mql5.com/en/signals/new
- or demo account was terminated based on inactivity
- or because many brokers are providing the demo accounts for limited time only.

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HELP! When trying to set up my demo account to give signals, im having an issue having the trades come through as signals. it gives me this message. "Authorization failed. Please check trading account data."
It is NOT my username and password. HELP!