OneDrive: Cannot finish backup

I have a problem that a backup from Win to OneDrive does not finish properly. I always get an error during the “Backend event: list”. While at first this step was successful after raising http-operation-timeout to 300 and reruning again (maybe unrelated, but I have seen some sporadic timeouts), it now happens every time. Any hints are appreciated.

Here is the error message:
Duplicati.Library.Backend.MicrosoftGraph.MicrosoftGraphException: InternalServerError: Internal Server Error error from request
https://graph.microsoft.com/v1.0/me/drive/root:/NAS-Musik:/children Method: GET, RequestUri: ‘https://graph.microsoft.com/v1.0/me/drive/root:/NAS-Musik:/children’, Version: 1.1, Content: ,
Headers: {
User-Agent: Duplicati/2.0.5.1
Authorization: Bearer ABC…XYZ
}
StatusCode: 500, ReasonPhrase: ‘Internal Server Error’, Version: 1.1, Content: System.Net.Http.StreamContent,
Headers:
{
request-id: 867aeab4-fa0e-4587-a6e2-b9abbf1f3d7c
client-request-id: 867aeab4-fa0e-4587-a6e2-b9abbf1f3d7c
x-ms-ags-diagnostic: {“ServerInfo”{“DataCenter”:“NorthEurope”,“Slice”:“SliceC”,“Ring”:“3”,“ScaleUnit”:“000”,“RoleInstance”:“AGSFE_IN_169”}}
Strict-Transport-Security: max-age=31536000
Cache-Control: private
Date: Tue, 24 Mar 2020 09:05:27 GMT
Content-Length: 238
Content-Type: application/json
}
{ “error”:
{ “code”: “generalException”,
“message”: “An error occurred in the data store.”,
“innerError”: { “request-id”: “867aeab4-fa0e-4587-a6e2-b9abbf1f3d7c”,
“date”: “2020-03-24T09:05:28” } }
}
bei Duplicati.Library.Main.BackendManager.List()
bei Duplicati.Library.Main.Operation.FilelistProcessor.RemoteListAnalysis(BackendManager backend, Options options, LocalDatabase database, IBackendWriter log, String protectedfile)
bei Duplicati.Library.Main.Operation.FilelistProcessor.VerifyRemoteList(BackendManager backend, Options options, LocalDatabase database, IBackendWriter log, String protectedfile)
bei Duplicati.Library.Main.Operation.BackupHandler.PreBackupVerify(BackendManager backend, String protectedfile) bei Duplicati.Library.Main.Operation.BackupHandler.d__20.MoveNext() — Ende der Stapelüberwachung vom vorhergehenden Ort, an dem die Ausnahme ausgelöst wurde —
bei System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
bei CoCoL.ChannelExtensions.WaitForTaskOrThrow(Task task) bei Duplicati.Library.Main.Controller.<>c__DisplayClass14_0.b__0(BackupResults result)
bei Duplicati.Library.Main.Controller.RunAction[T](T result, String& paths, IFilter& filter, Action`1 method) bei Duplicati.Library.Main.Controller.Backup(String inputsources, IFilter filter)
bei Duplicati.Server.Runner.Run(IRunnerData data, Boolean fromQueue)