AddIn does not start

AddIn does not start

Check the Logs in DiagViewer.
If it shows an ERROR in the GENERAL module which shows the exception:
Scada.Internal.DotNetAddInExtension.AddInIntegration.Startup Cannot startup Add-In .NET Extension for instance id 'e1d3....'. Exception information:System.InvalidOperationException The sequence does not contain a matching element. ...
...the reason for error is most likely in the AddIn itself.
The AddIn crashes before it reaches the 'Start' or 'Run' method. This could be because of a not existent library or a missing package. 
Check on the references of the AddIn and that they are available on the target machine.