Data Refreshing Issue in power bi report server

Hi,

I’m pretty new on PBRS and i have the same problem using scheduled refresh

I saved some reports (using powerbi dekstop 4 report server – january 2019) to our on-premise powerBI report server.

Most of this reports work fine with using scheduled refreshing but some of them return error "1055784932: Credentials are required to connect to the SQL source"

The data source looks OK, the Test connection is succesfull with the credentials i gave using basic authentication

I read some same issies, but i have not seen solutions, has someone any idea .....