a node (pve-3,172.16.2.3) is marked as questioned in web UI. what is found:
1. ssh to the node is ok, and vm is not dead, can be migrate to other node with [qm migrate --live] command.
2. restart pveproxy service did not fix the problem.
3. access to the node's ui(https://172.16.2.3:8006) is ok, but the node itself still shows in question mark.
3. after system reboot, everything will back to normal. (last time, just happen again today, not yet reboot now)

further info:
1. backup job was scheduled at 05:00(to pbs), /var/syslog/vzdump/192.log (#192 is the last vm in queue) shows the job was finished at 05:24 with no error.
2. the job status in web ui shows it's finished. but the round circle never stop rolling. (and "Duration" is still counting)
system info
I have no idea what is stucked.
1. ssh to the node is ok, and vm is not dead, can be migrate to other node with [qm migrate --live] command.
2. restart pveproxy service did not fix the problem.
3. access to the node's ui(https://172.16.2.3:8006) is ok, but the node itself still shows in question mark.
3. after system reboot, everything will back to normal. (last time, just happen again today, not yet reboot now)

further info:
1. backup job was scheduled at 05:00(to pbs), /var/syslog/vzdump/192.log (#192 is the last vm in queue) shows the job was finished at 05:24 with no error.
2. the job status in web ui shows it's finished. but the round circle never stop rolling. (and "Duration" is still counting)
system info
Code:
root@pve-3:~# pveversion
pve-manager/7.2-7/d0dd0e85 (running kernel: 5.15.39-1-pve)
root@pve-3:~# uptime
10:25:32 up 5 days, 19:18, 1 user, load average: 0.18, 0.35, 0.35
physical host is a intel nuc8i5, with 32GB RAM.
Code:
root@pve-3:~# pvecm status
Cluster information
-------------------
Name: cluster01
Config Version: 5
Transport: knet
Secure auth: on
Quorum information
------------------
Date: Fri Jul 15 10:42:44 2022
Quorum provider: corosync_votequorum
Nodes: 5
Node ID: 0x00000003
Ring ID: 1.de
Quorate: Yes
Votequorum information
----------------------
Expected votes: 5
Highest expected: 5
Total votes: 5
Quorum: 3
Flags: Quorate
Membership information
----------------------
Nodeid Votes Name
0x00000001 1 172.16.2.1
0x00000002 1 172.16.2.2
0x00000003 1 172.16.2.3 (local)
0x00000004 1 172.16.2.4
0x00000005 1 172.16.2.5
I have no idea what is stucked.