Trouble Connectin GBQ in Direct Query

Hello, I've a report which connects via direct query to Google Big Query. It worked for 1,5 years now and was never touched again since we first build it. Since today (or somewhen last week) we get an connection error. if I execute it locally it works all fine. This is the Error:

Failed to update data source credentials: [DataSource.Error] Web.Contents failed to get contents from 'https://www.googleapis.com/oauth2/v4/token' (400): Bad RequestHide details Activity ID: 5d802bff-ba65-44c8-b8e0-b3e07be0def1 Request ID: a9e0f96f-c22d-81ba-4201-3de6fa4938f9 Status code: 400 Time: Thu May 28 2020 15:19:23 GMT+0200 (Mitteleuropäische Sommerzeit) Service version: 13.0.13387.241 Client version: 2005.3.01208-train Cluster URI: https://wabi-north-europe-redirect.analysis.windows.net/