c# - ARSoft.Tools.Net SpfValidator.CheckHost() not responding -

i trying follow example:
https://docs.ar-soft.de/arsoft.tools.net/#spf%20senderip%20validation.html

var validator = new spfvalidator() {     helodomain = domainname.parse("example.com"),     localdomain = domainname.parse("receivingmta.example.com"),     localip = ipaddress.parse("192.0.2.1") };  spfqualifier result = validator.checkhost(ipaddress.parse("192.0.2.200"),  domainname.parse("example.com"), "sender@example.com").result;  

however, no matter ip's , url's use, checkhost() method not finish.

does know correct use, or example input parameters complete?

i expect exception if inputs invalid, possibly i'm doing wrong?

you're using same way i'm using it. works me. maybe have in firewall blocking performing queries?