have a macbook air 2020 that I have been backing up to a time machine hosted on a netgear readynas. been working fine for a while. now stopped. I think it stopped working around the time I upgraded to Big Sur. I have deleted the entire time machine instance on the nas and created a new instance - same error. I can connect to the drive, enter username/password just fine. after it spins for a while, it comes back with an error - "the backup disk image - ***.macbookair.sparsebundle" could not be accessed error 112. i have confirmed its using SMB as protocol on the nas. tried everything ... thoughts?/suggestions?