NAS to NAS Hyper-back up "Trust" setting won't stick on Target tab

Have had a 1522+ to a DS 220+ Hyperback up task running, established and did first back up locally and then brough off site and connected via Tailscale. Showed up as online and ran flawlessly for month with 3 am back up task after all local PCs did their active Bup4B tasks. All on latest/same DSM no recent updates.

1522 was restarted and now in the Hyper-backup task TARGET tab/page I tell it to Trust for authentication trust and it does change from red Fail to Green Trust. I close that out and then I go to run the task and it shows up as offline, fails and when I go back into the Target page it has c



hanged and shows as Fail even though it passed as was Green when I previously closed it out just a few minutes earlier. Thank you all. Checked all other settings and they are good including the same static IP address from Tailscale for Target NAS.

Check your certificates [Control Panel > Security > Certificates] on both devices. You may need to update or change one or both.