Cannot load model while connecting to Azure Sql Database (works fine on powerbi desktop)

Hi,

I've more than one dashboard connecting to an instance of Azure Sql Database using DirectQuey and they were perfectly working until this morning when I started getting this error:

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 check the technical details for more information. If you contact support, please provide these details.
Underlying Error: PowerBI service client received error HTTP response. HttpStatus: 503. PowerBIErrorCode: OpenConnectionError
OpenConnectionError: Failed to open the MSOLAP connection.
Correlation ID: 7f4e26d3-0a37-1fe1-4a11-3ef8a8b97b12
Activity ID: ed23bcd7-577c-4c97-9c7c-a62c75eeb10a
Request ID: 89876869-1cbe-e03d-be34-45fda508b1b7
Time: Mon May 18 2020 15:38:29 GMT+0200 (Ora legale dell’Europa centrale)
Service version: 13.0.13248.257
Client version: 2005.1.00976-train
Cluster URI: https://wabi-west-us-redirect.analysis.windows.net/

This happens on both Powerbi app and on our custom web application that uses Powerbi embedded. The dashboard works nicely on PowerBI desktop; I've also tried to create a fresh new dashboard for test connecting to the same Azure Sql DB without luck (same error).

Looking at the error I'm a bit confused as it refers to a MSOLAP connection while we're actually connecting to a standard SqlServer in Azure using the basic connection (user/pwd) without OAuth2 setting.

Lastly, if I try to refresh the dataset in Powerbi app from the settings page it works without issues.

Any hint would be much appreciated,

Thanks

Mike