NWL error and datasource issue

Hello,

I migrated our onPrem 2013 to onPrem 2016, using Nintex Workflow (not Live though), and did everythng to get InfoPath 2013 forms running. When I load the form I get a datasource error, but naturally Microsoft doesn’t name it. The form still loads but the data-filled DropDown controls that work in Dev don’t work on the SP2016 server. i can’t track it down and there’s nothing in the Event Logs on the server. But whjen looking at the Event Logs, I saw this error that has many instances over the last few days. It looks like it’s something for NW Live, which we are not using. Any idea how to fix this? Thanks in advance!

Load control template file /_controltemplates/15/NWLOnlineComponents.ascx failed: The expression prefix 'NWLResources' was not recognized.  Please correct the prefix or register the prefix in the <expressionBuilders> section of configuration.