Looks like you've correctly set up your Voice site to use the domain, but the domain itself currently isn't set up correctly.
Currently there's no A record present in the DNS record for hlra.org.uk.
So, head over to the control panel of your registrar and ensure there's an A record with IP address 184.108.40.206
Joe - Voice Admin
Thanks for this. We have gone back to IONOS and set up the A record successfully. We still seem to be having a problem with the domain name.
There are no A records set on hlra.org.uk or www.hlra.org.uk. So something weird is going on at IONOS (unless I'm checking the wrong domain name!?)