GraphAPI Error: Application is not registered in our store

I am currently getting the following error message from the GraphAPI:

Status Code: Forbidden
Microsoft.Graph.Communications.Core.Exceptions.ServiceException: Code: UnknownError
Message: {"errorCode":"7503","message":"Application is not registered in our store.","instanceAnnotations":[]}
Scenario Id: 4e4815b3-05c7-4e08-a0a2-0c9064289a05

Thanks to @itisslizz and @1fabi0 , I was able to get rid of the following error:

Microsoft.IdentityModel.Clients.ActiveDirectory.AdalServiceException: AADSTS700016: Application with identifier <APP ID> was not found in the directory <TENANT ID>.

from this issue: #426

Current Setup

1. Tenant A contains the fully configured Azure Bot Service.
2. Tenant A has no 365 subscription (including Microsoft Teams)
3. Tenant B has the 365 subscription (including Microsoft Teams).
4. Tenant B has no Azure subscription.

Additional Notes:

1. The bot service app (in Tenant A) has admin consent and permissions granted in Tenant B.

Any recommendations for this?

No repository files, tests, or entry points are identified. Start by reproducing the Microsoft Graph Communications request with the stated cross-tenant Azure setup and inspect the project entry points for Graph authentication and application registration. Done means the error has a documented resolution or a repository change with verification.