Error codes are seldom very enlightening. A search of the log files for backupd entries might provide more information.

If I had to interpret just from the two error codes I would suspect at that point in time TM had attempted to open the TM drive and for whatever reason it could not be contacted. That could imply...
  • The drive had for one reason or another been dismounted (I have one that inexplicably does that once in a while — I don't use it except for experimental work — which may be why it disconnects) 😒
  • drive response was slow and the contact attempt timed out 🙄
  • If the TM volume is used by more than one Mac it was busy when your system attempted to contact it 👾
  • if it is a network attached drive, network traffic might have prevented the connection. 😳
  • an internal system error 😱
  • nothing to worry about unless it recurs 🤔
  • recurs at an increasing frequency 😭


If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein