Live connection to SSAS

Hey XeniaLi ,

You're experiencing a recurring issue where Power BI Report Server fails to connect to a live SSAS (SQL Server Analysis Services) model. This issue:

• Happens randomly to different users

• Only affects live-connected reports

• Fixes itself without intervention, then reoccurs

• Does not affect reports using import mode

From the screenshots:

• Error mentions ConceptualSchemaProxy.execute in the console

• Error popup shows: "We couldn't connect to the Analysis Services server"

Resolve Tecnique

1. Kerberos Delegation Issues

Live connections to SSAS require Kerberos authentication to impersonate users. If this setup is incomplete or misconfigured, users will see connection failures.

What to do:

• Ensure Service Principal Names (SPNs) are correctly registered:

  • For Report Server: HTTP/yourReportServerName

  • For SSAS: MSOLAPSvc.3/yourSSASServerName

• Check that Constrained Delegation is configured: In Active Directory, allow the Report Server’s service account to delegate to the SSAS service

• Confirm that your live connection uses EffectiveUserName to pass user identity for RLS

2. Alias and DNS Resolution

If your friendly alias doesn’t consistently resolve or isn’t trusted by all users’ browsers, it can trigger connection issues or CORS (cross-origin) problems.

What to do:

• Confirm that the alias works for every user via ping or nslookup

• Add the alias (like http://reports.yourcompany.com) to the Trusted Sites list or Intranet Zone via Group Policy

• Ensure the DNS alias (CNAME) doesn’t conflict with Kerberos SPNs

3. Performance Bottlenecks on SSAS Server

Temporary resource shortages (CPU, memory, etc.) on the SSAS server can block or delay connections, especially under heavy load.

What to do:

• Monitor SSAS performance using:

  • Performance Monitor

  • SQL Profiler

  • Resource Monitor

• Check whether memory constraints or process restarts are causing downtime

• Look for query execution delays or processing backlogs

4. RLS-Related Identity Problems

Row-Level Security depends on the correct user identity being passed to SSAS. If this fails (e.g., due to delegation issues), users may be denied access randomly.

What to do:

• Confirm that user identity flows properly from the report to SSAS

• Test user access by connecting to the SSAS model in SSMS (SQL Server Management Studio) using their credentials

• Review RLS filters to make sure they’re not too restrictive or misconfigured

5. Clock Synchronization Issues

If the system time differs significantly between user machines, the report server, or SSAS, authentication tokens may become invalid due to clock skew.

What to do:

• Ensure all servers and user devices are syncing time with a reliable NTP source

• Double-check domain time policies

• Reboot servers if needed to apply new time settings

For detailed information:

Configure Kerberos Constrained Delegation for Analysis Service

Troubleshoot Analysis Services Connection Issues in Power BI Report Server

Set SPNs for Power BI Report Server

Kerberos Configuration Manager for SQL Server

If you found this solution helpful, please consider accepting it and giving it a kudos (Like) it’s greatly appreciated and helps others find the solution more easily.

Best Regards,
Nasif Azam