Provisioned Yealinks, Gigasets and Panasonic's use DNS-NAPTR/SRV to connect to the Kwebbl Platform. Some old(er) or non-standard DNS Servers do not support NAPTR or SRV requests and thus the phone is unable to register.
To see if your phone is affected by this issue, check the following settings on the Account page via the phone’s Web interface:
- Domain is set to notls.<domain>, eg notls.sip.kwebbl.net;
- Port is set to 0;
- Protocol is set to DNS-NAPTR;
- Account shows registration failed.
If your phone matches the settings above, please change the DNS Server that your phone uses. You could try to use the public Google DNS Servers (220.127.116.11 Primary and 18.104.22.168 Secondary), which are known to work correctly.