Paginated reports error - getting data from semantic model

[ahmedshalabyy12]

Hello ,

I receive this error while I try to create a paginated report and fetch the data from a certain workspace (A), however it works fine with another workspace (B), therefore what's the reason for that ?

Edit :  I am an admin of both workspaces 

Error Details :
Microsoft.ReportBuilder.Diagnostics.ErrorHandling.ReportBuilderException: Object reference not set to an instance of an object. ---> System.NullReferenceException: Object reference not set to an instance of an object.
at Microsoft.ReportDesigner.DatasetDetailsExtensions.IsMyWorkspace(DatasetDetails datasetDetails)
at Microsoft.ReportDesigner.DatasetBrowsePbiViewModel.<InitializeWorkgroupDatasets>b__30_0(DatasetDetails d)
at System.Linq.Lookup`2.Create[TSource](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at System.Linq.GroupedEnumerable`3.GetEnumerator()
at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
at Microsoft.ReportDesigner.DatasetBrowsePbiViewModel.<InitializeWorkgroupDatasets>d__30.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.ReportDesigner.DatasetBrowsePbiViewModel.<OnSelectedGroupChanged>d__23.MoveNext()
--- End of inner exception stack trace ---
Thank you 

[ahmedshalabyy12 · Accepted solution]

Hello @AshokKunwar ,

Thank you for your efforts problem is solved what I did I connected from another VM
cuz checking if the vpn in my pc blocking the connection and it worked .

I don't know how the vpn blocking the connection despite I can connect to another workspace .

[AshokKunwar]

Hii @ahmedshalabyy12 

If this helped, please mark it as a Solution and leave a Kudo! It helps the community find the answer faster."

[AshokKunwar]

Hii @ahmedshalabyy12 

For this error 

Step 1: Check Workspace Version and Permissions

​Paginated reports require specific workspace configurations.

• ​Workspace Type: Ensure Workspace A is a V2 (New) workspace. Legacy V1 workspaces can cause retrieval errors.
• ​Permissions: Confirm you have Member or Admin roles in Workspace A. Even if you can see it in the service, Report Builder requires higher-level permissions to browse the semantic models.
• ​Build Permission: Ensure you have "Build" permissions on the specific semantic model you are trying to reach.

​Step 2: Re-authenticate the Session

​Sometimes the local token for one workspace becomes "stale" or corrupted.

1. ​Close Power BI Report Builder.
2. ​Go to File > Options (if accessible) or simply Sign Out from the top-right corner.
3. ​Restart your computer to clear any cached network credentials.
4. ​Open Report Builder and Sign In again before attempting to connect to the dataset.

​Step 3: Check for "Broken" Semantic Models

​The NullReferenceException is often triggered by a single "corrupt" or "orphaned" dataset in a workspace.

• ​Log into the Power BI Service and look at Workspace A.
• ​Check if there are any datasets with a red alert icon (Gateway disconnected or credentials expired).
• ​If a dataset in Workspace A has no owner (owner left the company), it can return a "Null" value to the Report Builder API, crashing the entire list retrieval for that workspace.

​Technical Summary

​The stack trace points to IsMyWorkspace failing. This usually happens when the workspace contains an object that Report Builder cannot categorize, such as a dataset without a valid owner or a workspace that has not been upgraded to the modern experience.

​If checking the workspace owner or re-signing in fixes the connection for Workspace A, please mark this as the "Accepted Solution"!

[ahmedshalabyy12]

I am an admin in the workspace but how to check this solution

• ​Workspace Type: Ensure Workspace A is a V2 (New) workspace. Legacy V1 workspaces can cause retrieval errors.

[AshokKunwar]

@ahmedshalabyy12 

If you are an Admin, you can tell by looking at the Workspace Settings:

• ​Open Workspace A in the Power BI Service.
• ​Click on Settings (the gear icon near the top right) or the three dots (...) next to the workspace name.
• ​Look for a "Contact list" or "Workspace ID" in the General tab.
• ​The Key Indicator: If you see the "Manage access" pane where you can assign roles like Contributor, Member, or Viewer, you are on a V2 (New) workspace. Legacy V1 workspaces relied on Office 365 Groups for permissions and lacked these specific Power BI roles.

​2. Check the Licensing (Capacity Settings)

​Paginated Reports require specific capacity settings to work correctly across different workspaces. Even if you are an Admin, if the workspace is not backed by the right capacity, Report Builder might throw a "Null" error when trying to fetch the list of datasets.

• ​In Workspace Settings, go to the Premium tab.
• ​Ensure the workspace is assigned to Premium Capacity, Premium Per User (PPU), or Fabric Capacity.
• ​If Workspace B is on a Premium capacity but Workspace A is on "Shared" (Pro), this is likely why Report Builder works for one and not the other.

​3. Check for Service "Orphans"

​Since the error in Report Builder was IsMyWorkspace failing, it could be that the "Owner" of the workspace or the specific semantic model has been deleted from your Entra ID (Active Directory).

• ​Go to the Semantic Model settings in Workspace A.
• ​Check the Gateway connection and Data source credentials.
• ​If the "Owner" listed is no longer with the company, you must click Take Over to become the owner of the model. This often resolves "Object reference not set" errors because it "re-links" the object to a valid user.

If checking the workspace owner or re-signing in fixes the connection for Workspace A, please mark this as the "Accepted Solution"!