Was working on az ml cli v2 to deploy real-time endpoint with command az ml online-deployment through Azure pipeline. had double confirmed that the service connection used in this pipeline task had added the permissions below in Azure Portal but still showing the same error.
ERROR: Error with code: You don't have permission to alter this storage account. Ensure that you have been assigned both Storage Blob Data Reader and Storage Blob Data Contributor roles.
Using the same service connection, we are able to perform the creation of online endpoint with az ml online-endpoint create in the same and other workspaces.
Issue was resolved. I did not change anything in the service principal and running it on second day using same yml got through the issue. I guess there might be some propagation issue, but longer than usual.