When executing the Proxmox VE special agent manually, I get the following error:
OMD[mysite]:~$ /omd/sites/mysite/share/check_mk/agents/special/agent_proxmox_ve '-u' 'checkmk@pve' '-p' 'PASSWORD' '--port' 8006 '--no-cert-check' '--timeout' 60 'pveiloon'
Caught unhandled TypeError('NoneType' object is not iterable) in /omd/sites/mysite/lib/python3/cmk/special_agents/utils/agent_common.py:135