Hi Maliming, thank you for your response but we are still unable to get this working.
We noticed that this same scenario has been brough up before: https://abp.io/support/questions/9140/Forward-tenant-as-query-string-to-Authentication-Server
This is the tenant resolver (relevant part) we tried to implement in the frontend (angular) and it does append the "__tenant" to the querystring with the right value. But the login after entering the right creds send us back to the app which immediately send us back to the login but this time there is no tenant switcher (it was at first) and no creds are valid at all at this point.
