You are trying to access an existing mount point, or create a new mount point, and it fails with an error message.
Invalid Mount Exception:The backend could not get tokens for path /mnt.
The root mount path (/mnt) is also mounted to a storage location.
If /mnt is listed with a source, you have storage incorrectly mounted to the root path..
You should unmount the root mount path.
You can now access existing mount points, or create new mount points.