Error Help - DataFormat.Error: Invalid cell value '<ccon>#NAME?'.. </ccon>. The exception was raised

Hello - Hoping someone can help with this.

My report is pulling data from excel files in sharepoint. We are combining many excels into one table. Recently, this error is popping up and I can't find where the problem is. I have done the following:

- Gone through the power query steps from the bottom up looking for the error -- no errors were shown and the data looks fine in the pbix, but error is thrown when refreshing in the service.

- I have looked at the source files for fields that might be causing this error (those starting with special characters). I did find some and fixed. -- refresh still throwing this error

- I have added a step into each file import, prior to promoting headers to replace errors with nothing -- refresh is still throwing an error.

Any thoughts?