I built this unraid server about 6 months ago. It'ss been working fine for the most part.  I do have the server on a 24/7 UPS backup but somehow the UPS itself malfucntioned. Long story short, it was an unclean shutdown and when power was restored and the server came back online it did not automatically started a parity check, because one of the disk (disk1) was showing as "Unmoutable disk Present". Not knowing What exactly to do next I tried rebooting the server, plugged in and out the disk a few times and viola it came back on like a charm. Anyways, after that I cant exactly remember wether it did start the parity check automatically or I did it. But 28 hrs later it gave out a warning that 515 errors were found after Parity check completed. I always have the server to auto correct errors on scheduled parity checks (once a month) but I don't know if this setting was enforced. I havent done anything on the server for the parity since then cuz quiet hoenslty I dont even know what to do.

Attaching diagnosis here in hopes to get proper advice. 
FYI I am a windows guy and not familiar with commanad line.

tower-diagnostics-20231116-2115.zip

Just run a correcting check, it's normal after an unclean shutdown to have some sync errors.

On it. Will get back in 28 hrs. 

Well. It took less longer this time and went pretty well. Parity checked with no errors.

Thanks alot Jorge.