Permission denied while trying to mount Azure Fileshare volume in a Container App

Question

I receive this error when trying to create a new Container App revision.

{"TimeStamp":"2024-09-13 14:41:30 \u002B0000 UTC","Type":"Warning","ContainerAppName":"io2-api","RevisionName":"****","ReplicaName":"****","Msg":"Container \u0027io2-api\u0027 was terminated with exit code \u0027\u0027 and reason \u0027VolumeMountFailure\u0027. One or more errors occurred. (Shell command exited with non-zero status code. StatusCode = 32 | StdOut =  | StdErr = mount error(13): Permission denied\nRefer to the mount.cifs(8) manual page (e.g. man mount.cifs) and kernel log messages (dmesg)\n) (Shell command exited with non-zero status code. StatusCode = 32 | StdOut =  | StdErr = mount error(13): Permission denied\nRefer to the mount.cifs(8) manual page (e.g. man mount.cifs) and kernel log messages (dmesg)\n)","Reason":"ContainerTerminated","EventSource":"ContainerAppController","Count":7}
{"TimeStamp":"2024-09-13T14:41:31Z","Type":"Normal","ContainerAppName":null,"RevisionName":null,"ReplicaName":null,"Msg":"Shutting down events stream. Max connection open time reached","Reason":"CloseConnectionDueToTimeout","EventSource":"ContainerAppController","Count":1}

This is my bicep file:

volumeMounts: [
            {
              mountPath: '/home/storage'
              volumeName: 'dev-volume'
            }
          ]
        }
      ]
      volumes: [
        {
          name: 'dev-volume'
          storageName: 'container-volume'
          storageType: 'AzureFile'
        }
      ]

I configured the container-volume name in the Container App Environment with staging-storage (storage account) and api (fileshare).

The Container App environment uses a managed identity and I configured the SMB contributor role.

The container is in the same VNET as the Storage and this VNET is allowed access.

I have the same setup for a different resource group and it works fine there. In the Staging resource group I can't get this to work. I hope somebody can help me out or at least give me some lead as I am out of ideas.