This issue occurs when the backup takes longer than MDOQ waits. MDOQ by default waits a very long time, however depending on multiple things, your server max reach and exceed this limit.
If you receive this error, simply wait a little time and run the backup again again, MDOQ is smart enough
to know the other one will have still been running and will pick up from where it left off.
If you consistently hit this issue, we would recommend running the following reports, which
should highlight and help you remove any issues