I work with Power BI reports against a live PBI model on the service for my customer. After changing a report file (August version of PBI desktop) and handing over to the customer, the error 'Sequence contains no matching element' is raised. I was able to solve this by logging in with my own account on the customer's PC, loading the report, changing accounts.
However, the customer now downloads a report that has been published already (working flawlessly for two weeks). The same error occurs when trying to open the report with PBI Desktop. This happens while the user is logged in at the tenant that hosts the model, so it should work just fine (and it did earlier).