No need to talk to your Broker
MetaTrader4 Server side has nothing to do with this.
Check your localhost Terminal settings
There might be several reasons, why the EA was working ( "DID work" as you post it )
and still you get an error.
An MT4.Terminal.Profile
change can also cause this to happen.
An MT4.Terminal.LogAnotherUser
change can also cause this to happen.
An MT4.Terminal.Graph
change of { Symbol
| Period
} can also cause this to happen.
Check Tools
> Options
> Expert Advisor
[TAB] for active values in respective check-boxes for all the above.
Check, if you are correctly logged-on to a correct ( not canceled ) trading account.
Check, if your connection is green / working
Check, if your trading Symbol has active market ( open trading hours )
If still in troubles, send a few OrderSend()
-s with PrintScreen
-s and copy responses from Log-File & post here.