Unexpected EOF during handshake

[dries]

Has this something to do with my issue? If it does, will there be a remediation?

I also tried to add an extra layer of security by only adding the IP-address of the checkmk server under “OnlyFrom” which you can add by adjusting “C:\ProgramData\checkmk\agent\check_mk.user.yml”, but after restarting the service, OnlyFrom remains empty

OMD[mon]:~$ nc 192.168.x.x 6556 | grep OnlyFrom
OnlyFrom:

@mschlenker

Is the agent controller on the Proxmox host the same Checkmk major version? There has been some changes that break agent registration of 2.2.0 agents on 2.4.0 servers. Only registration is affected, already registered 2.2.0 agents continue to work with Checkmk 2.4.0.