Blank output from checkmk agent

CMK version:
OS version:
CentOS Linux release 7.9.2009 (Core)

Problem is that from the checkmk server im able to telenet, im also able to do nc to the server and getting the whole agent output. If i go in the browser everything i blank. Any suggestions?

Checkmk version 2.0.0p12
Try license usage history update.
Trying to acquire lock on /omd/sites/tten/var/check_mk/license_usage/next_run
Got lock on /omd/sites/tten/var/check_mk/license_usage/next_run
Trying to acquire lock on /omd/sites/tten/var/check_mk/license_usage/history.json
Got lock on /omd/sites/tten/var/check_mk/license_usage/history.json
Next run time has not been reached yet. Abort.
Releasing lock on /omd/sites/tten/var/check_mk/license_usage/history.json
Released lock on /omd/sites/tten/var/check_mk/license_usage/history.json
Releasing lock on /omd/sites/tten/var/check_mk/license_usage/next_run
Released lock on /omd/sites/tten/var/check_mk/license_usage/next_run
  Source: SourceType.HOST/FetcherType.PROGRAM
[cpu_tracking] Start [7f158f5a8430]
Calling: /omd/sites/tten/share/check_mk/agents/special/agent_proxmox_ve '-u' 'checkmk@pve' '-p' 'checkmk' '--port' 8006 '--no-cert-check' '--timeout' 60 '--log-cutoff-weeks' 2 'portainer'
[ProgramFetcher] Fetch with cache settings: DefaultAgentFileCache(base_path=PosixPath('/omd/sites/tten/tmp/check_mk/data_source_cache/special_proxmox_ve/portainer'), max_age=MaxAge(checking=0, discovery=120, inventory=120), disabled=False, use_outdated=False, simulation=False)
Not using cache (Too old. Age is 119 sec, allowed is 0 sec)
[ProgramFetcher] Execute data source
Write data to cache file /omd/sites/tten/tmp/check_mk/data_source_cache/special_proxmox_ve/portainer
Trying to acquire lock on /omd/sites/tten/tmp/check_mk/data_source_cache/special_proxmox_ve/portainer
Got lock on /omd/sites/tten/tmp/check_mk/data_source_cache/special_proxmox_ve/portainer
Releasing lock on /omd/sites/tten/tmp/check_mk/data_source_cache/special_proxmox_ve/portainer
Released lock on /omd/sites/tten/tmp/check_mk/data_source_cache/special_proxmox_ve/portainer
[cpu_tracking] Stop [7f158f5a8430 - Snapshot(process=posix.times_result(user=0.010000000000000231, system=0.010000000000000009, children_user=0.39, children_system=0.12, elapsed=0.5499999998137355))]
[cpu_tracking] Start [7f158f5a87c0]
  Source: SourceType.HOST/FetcherType.PROGRAM
No persisted sections loaded
  -> Add sections: []
Received no piggyback data
Loading item states
Trying to acquire lock on /omd/sites/tten/tmp/check_mk/counters/portainer
Got lock on /omd/sites/tten/tmp/check_mk/counters/portainer
Releasing lock on /omd/sites/tten/tmp/check_mk/counters/portainer
Released lock on /omd/sites/tten/tmp/check_mk/counters/portainer
[cpu_tracking] Stop [7f158f5a87c0 - Snapshot(process=posix.times_result(user=0.009999999999999787, system=0.0, children_user=0.0, children_system=0.0, elapsed=0.009999999776482582))]
[special_proxmox_ve] Version: unknown, OS: unknown, execution time 0.6 sec | execution_time=0.560 user_time=0.020 system_time=0.010 children_user_time=0.390 children_system_time=0.120 cmk_time_ds=0.020

did you try to run connection test from web? And ddi you try to run agent on your linux machine to see agent output?

Best regards,

Connection test from web are blank. But if doing telnet from checkmk server to client i get the output.
Now i also tried to installing a docker to test and here i can get the output so im guessing its server related?

What method are you using for the connection? I’ve seen this behaviour when people tried connecting using SSH using a non-root user and the user that is used to run the checkmk agent does not have sufficient privileges.

huh? checkmk agent on port 6556?

Sorry, my bad. Though you could have configured it different in CheckMK.

What is the output of

cmk -d <clientname>

when run as the site user on the CheckMK server? Is that also empty?

This has same output as the browser. Blank

I have jusst downloaded the client with default configuration. Special Client?

Yes i have a proxmox setup here. And it is configured API integrations and Checkmk agent.

Btw, i tested with a new docker setup and here it works out of the box.

Not sure what you mean by special agent.