Power bi report server reports error after monthly update applied, An unexpected error occurred.

Hi, gregboothdelt 

Although you mention reporting a connection to SQL Server, the error message mentions Analysis Services. confirm whether there are any hidden or legacy connection string configurations that might point to Analysis Services. Try connecting to SQL Server in Power BI Desktop using the same connection string to see if the Try connecting to SQL Server in Power BI Desktop using the same connection string to see if the connection is successful.
Also check the SQL Server error log for any relevant errors or warnings.
If conditions permit try restarting the Reporting Server Service / SQL Server Service, a simple restart can resolve temporary issues or inconsistent status.
If the problem occurs after an update, consider uninstalling the latest update and reverting to the previous stable version. After resolving any potential configuration issues, try applying the update again.

hackcrr

If this post helps, then please consider Accept it as the solution and kudos to this post to help the other members find it more quickly