Did the error occur on more than one device?
Anyway, I noticed this in the log:
Feb 21 17:40:16 osmc mediacenter[758]: 2020-02-21 17:40:16.403022 apt_cache_action.py exception value : E:The repository 'http://apt.osmc.tv stretch Release' does no longer have a Release file.
This is very similar to this thread: Update Error The OP in that thread now reports that the problem has gone away, so can you please try again?