could not resolve hostname: "applicationserver.ims.mnc001.mcc001.3gppnetwork.org"

[zmkglb]

open5gs-config.zip

Open5GS Release, Revision, or Tag

v2.7.1

Steps to reproduce

I installed kamailio-ims and open5gs according to the instructions https://open5gs.org/open5gs/docs/tutorial/02-VoLTE-setup/, but I used Pyhss https://github.com/nickvsnetworking/pyhss rather than FoHSS.
I have two connected phones and the registered volte status is on on both, but when I make a call, the call is dropped and an error appears in the iscsf console:

Logs

No response

Expected behaviour

Please help me to resolv problem

Observed Behaviour

Please help me to resolv problem
pcap.zip

eNodeB/gNodeB

custom

UE Models and versions

No response