Hello Peter
The domain enernova.ch is blocked completely by Internet Guard.
Maybe you could try again to go trough the online formular, normally you should get an answer or the domain should be whitelisted.
Did you scan/check your server for any abnormal files or behaviour?
If there are different servers for any subdomain in enernova.ch, you might also need to have a look at those.
It seems that there was some malware infection present last year:
https://urlhaus.abuse.ch/host/enernova.ch/
If the malware is not present anymore, it might be, that some lists did not remove the domain.
https://www.virustotal.com/gui/url/f30da4f67961d7e32dadf1303dd046eaffd70edf8bcbcfae63a12a5267cdc6b2/...
Regards
Stephan