JorgeB

Try uninstalling/reinstalling the My Servers plugin, rebooting the server should also help.

You are having issues with this cache disk:
 
Model Family: Western Digital Purple (Pro) Device Model: WDC WD30PURX-64P6ZY0  
Run an extended SMART test on it.

There was another user with the same device, a quirk has already been added, it should work for the next Unraid release.

There are errors identifying multiple disks, swap cables from a known good to a known bad and see if it follows cable or disk.

Check/replace cables but if disk1 is no longer detected you'll need to rebuild the array without it.

Mar 2 10:08:17 Oracle kernel: nvme0n1: I/O Cmd(0x2) @ LBA 2272992, 32 blocks, I/O Error (sct 0x2 / sc 0x81) MORE DNR Mar 2 10:08:17 Oracle kernel: critical medium error, dev nvme0n1, sector 2272992 op 0x0:(READ) flags 0x1000 phys_seg 1 prio class 0  
Yep, looks like a failing device.

Start here:
https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?do=findComment&comment=819173
 
For the PCIe errors see if this helps:
https://forums.unraid.net/topic/118286-nvme-drives-throwing-errors-filling-logs-instantly-how-to-resolve/?do=findComment&comment=1165009
 

This type of errors can be intermittent, if it happens again and it's logged as a disk problem as these were, consider replacing it.

Stop array, unassign all pool devices, start array, stop array, re-assign all pool devices, start array and you're done.

It's not logged as disk problem , if possible try connecting that disk (and the other one from the same model) to the onboard SATA controller, this can also help:
 
 
 

You just need to backup the /config folder from the current flash drive, all you need is there.

That's correct, start the array to begin the parity sync.

https://wiki.unraid.net/Manual/Storage_Management#Rebuilding_a_drive_onto_itself

Feb 28 23:25:01 Truffle kernel: nvme nvme0: I/O 102 QID 3 timeout, aborting Feb 28 23:25:01 Truffle kernel: nvme nvme0: I/O 34 QID 4 timeout, aborting Feb 28 23:25:04 Truffle kernel: nvme nvme0: I/O 65 QID 2 timeout, aborting Feb 28 23:25:04 Truffle kernel: nvme nvme0: I/O 66 QID 2 timeout, aborting Feb 28 23:25:31 Truffle kernel: nvme nvme0: I/O 102 QID 3 timeout, reset controller Feb 28 23:25:34 Truffle kernel: nvme nvme0: I/O 8 QID 0 timeout, reset controller Feb 28 23:27:04 Truffle kernel: nvme nvme0: Device not ready; aborting reset, CSTS=0x1  
Device dropped offline, a power cycle should bring it back, not just a reboot, if it does this can sometimes help with these issues:
 
On the main GUI page click on the flash drive, scroll down to "Syslinux Configuration", make sure it's set to "menu view" (top right) and add this to your default boot option, after "append initrd=/bzroot"
nvme_core.default_ps_max_latency_us=0 pcie_aspm=off e.g.:
append initrd=/bzroot nvme_core.default_ps_max_latency_us=0 pcie_aspm=off
See if it helps.

File system has issues, suggest backing up anything important then try to repair, or possibly better just format the pool and restore the data.

Yep.
 
A backup, you can do it manually of for example with CA backup and restore.

Run it again without -n or nothing will be done, and if it asks for -L use it.

It's using 62.6GiB
 
total used free shared buff/cache available Mem: 62Gi 1.8Gi 905Mi 1.1Gi 59Gi 59Gi  
You can ignore the 32

See here:
https://forums.unraid.net/topic/132930-drives-and-usb-devices-visible-in-bios-not-available-once-booted-asus-wrx80-sage-5965wx/?do=findComment&comment=1208035
 

Try using the disk path/share, user share always add some overhead.

Start here:
https://forums.unraid.net/topic/46802-faq-for-unraid-v6/?do=findComment&comment=819173
 

This should have been posted in the UD support thread, go to UD settings nad make sure the SMB settings are set to public, if that doesn't help post here:
 
 

Feb 24 13:22:14 unraid kernel: BTRFS info (device loop3): bdev /dev/loop3 errs: wr 0, rd 0, flush 0, corrupt 25, gen 0  
libvirt.img is also corrupt, but with that one if you re-create it you will need to reconfigure the VMs, do you have a backup?
 
Snapshots are supported, it's how I backup my VMs, there's just no GUI support, but you can take them manually (or with a script) or by using the Snapshot plugin.

https://wiki.unraid.net/Manual/Storage_Management#Rebuilding_a_drive_onto_itself

Check filesystem on disk4, run an extended SMART test on disk5.