Data Flow error: 'We cannot convert Type to Table type'

[MPMP]

I have a power Bi report which is connected to data flow, excel on share point and SQL data sources. The report is published to workspace and it was working(scheduled refreh) fine until last week. This on monday the data source credentials for data flows on Power BI services(Data Set section) started throwing this error message shown in the screen shot.

When I click on the option to Edit Credentials, it will pop up the authention window where I chose OAuth authentication method with Organizational privacy level and when I hit sigin it throws a strange error message as shown in the screenshot below

I have no idea what could be the reason for this issue, anyone faced a same issue or have any idea on how to fix it please help me.


Thank you

[MPMP]

Hi Phil, 
Thanks for your suggestion, I looked into the dataflows but I didn't find any issues, they all look pretty good

[PhilC]

The issue might not be credentials.  That type of message is similar to what you receive when transforming data.  Maybe go into the Dataflow and edit the query and see if there is an issue with it, possibly caused by new data.