ERROR for "CreatePullPointSubscription"

[maxxom64]

Hi, after I start the application, it connects to MQTT and my ONVIF camera device. But then it shows

[1641555221859] ERROR (ONVIF/ on xxx.xxx.xxx.xxx): CreatePullPointSubscription

How can I find out more on the root cause for that ERROR? Looks for me like it can't establish a "Subscription" to the Camera.
Any log, where I can find more information? Or a way, how I can enable more Debug infos?

[ratsputin]

A common problem I've seen here with other ONVIF subscription implementations is that the camera can't resolve the hostname of the machine where onvif2mqtt is running. Make sure you have your cameras pointing to a DNS server that can resolve that hostname and that you don't have a firewall between them and where onvif2mqtt is running.