Cannot load model error on Report connected to Premium XMLA endpoint in Premium

[Anonymous]

We created a Power BI Dataset based on Azure SQL DB & Sharepoint.  It is published to a Gen2 Premium workspace.  We have validated that the workspace has XMLA enabled. 

We have several reports which connect to the XMLA endpoint.  In Power BI desktop, all is well and the reports look great.  

We published the reports to the same workspace as the DataModel, and when we access the report, and receive the error "Cannot Load Model".  It does not matter if we publish from desktop or use "Get Data" in the service, we get the same error.  
Here are the error details: 

Cannot load model
Couldn't load the model schema associated with this report. Make sure you have a connection to the server, and try again.
Please try again later or contact support. If you contact support, please provide these details.
Activity ID: e18721f9-0064-48ce-8a9b-8df4c0f0fc21
Request ID: 360f1ac5-9b98-aff7-0cde-996e2cf4e49a
Correlation ID: 3965ed48-7367-2211-3ce8-51f7f555b039
Time: Wed May 06 2020 16:25:43 GMT-0700 (Pacific Daylight Time)
Service version: 13.0.13035.262
Client version: 2004.2.00695-train
Cluster URI: https://wabi-us-east2-redirect.analysis.windows.net/

[jeroenterheerdt · Accepted solution]

Hi @Anonymous this is actually a known issue. It is documented here: https://docs.microsoft.com/en-us/power-bi/service-premium-connect-tools#power-bi-desktop-in-live-connect-mode.

You will be happy to know that we are working on it and should have something ready soon.

[duncanmi]

Hi, is this still an issue?

In the scenario, when a PBI Desktop Report is authored by a B2B Guest, they have to connect to the external tenant's PBI Service Datasets using XMLA over Analysis Services (only option because they can only see their home tenant PBI Datasets when trying to get data from PBI Datasets), the reports work fine until they are published to the external tenant service.
Is there any alternative for B2B Guest Desktop authoring and publishing against existing PBI Datasets in another tenant?

[duncanmi]

Just to answer my own query here, a workaround which I managed to figure out

1. Use a local tenant account to author a blank report using "Power BI Datasets", connect to the same service Dataset and save the .pbix
2. Rename the pbix to .zip, open and extract the "connections" file
3. Rename the guest-created report .pbix to .zip
   (this file is using "Analysis Services" connection to XMLA) 
4. overwite the "connections" file in guest .zip in [3] with file extracted in [2]
5. Revert the guest-created report .zip to .pbix

Now when the guest uploads their .pbix file it will be using a "Power BI Datasets" datasource.

PS: this confirms that the limitation of a guest authoring reports against external tenant Power BI Service Datasets is simply a UI limitation of PBI Desktop; PBI Desktop should simply ask which tenant to connect to and generate the correct "connections" file