My checks don't run automatically any more

Using an older Icinga build that was working for a while but since several months, I have noticed that the checks do not run automatically

If I run them manually, they work, but then when the next scheduled check would take place, nothing happens and I guess the little clock appears.

What I would like help with if possible please, is a hint, I have no idea where to look for this. I had a look in Icinga2.log but didn’t find much and tried to look it up on these forums.

Setup is 2 masters, 2 satellites, all in a very isolated, secure zone.

Is the checker anabled?
What is the output of: icinga2 feature list
Are active host checks enabled? /icingaweb2/monitoring/health/info

Disabled features: compatlog debuglog elasticsearch gelf icingadb influxdb livestatus opentsdb statusdata
Enabled features: api checker command graphite ido-mysql mainlog notification perfdata syslog