Hi, @LoolyJar
Thank you for posting in Microsoft Q&A forum.
- Make sure the SQL Server reporting services are up and running.
- Check SSRS log to see if there any error.
- We may encounter the report builder access error when we don't have SQL certificate installed on our computer. Exporting the ConfigMgr SQL Server Identification Certificate from SCCM server and importing into the computer resolves the report builder access error.
For more details, we may check this article:
https://www.prajwaldesai.com/sccm-sql-server-report-builder-access-error/
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