The Nintex Workflow Stored procedure "GetWorkflowDataToPurge" is missing
The most common occurrence for this behavior is that the Nintex Database isn't up to date (Most likely to occur after an product upgrade). You can either check and confirm that the database is up to date by navigating to Central Admin > Nintex Admin (Nintex Workflow Management) > Database Management > If you see an **update now** indicator next to the database version, select it.
If this doesn't work, you can also run:
Run the NWAdmin.exe -o UpgradeDatabases