Refreshing dataset (webservice) with SharePoint source

Do more people get this error with the refresh of a dataset in the power bi service? When I look at the references (login) I do not have a login error.

I can publish my PBIX, but refreshing fails everytime.

Also when I refresh these references and then again load the dataset, I still get this error message. Someone the golden tip how to fix it?

First I got it for another dataset, removed it for testing. But this does not help either. He then simply switches to another dataset with the error.

There was an error when processing the data in the dataset.
Please try again later or contact support. If you contact support, please provide these details.