Gigaset phones can't access server on Virgin - suggestions?

I recently moved and switched to Virgin Media. My Gigaset C475 voip phones seemed to work for about the first two weeks - although with fading sound, and then awful crackle - but for the last month simply say "Server not accessible" on the screen and admin panel. Calls to my voip numbers are cut off without ringing so the numbers are unusable. Nothing I do to the Gigaset settings makes a difference.

I've tried changing some of the - very limited - settings on the VM Hub 3 interface but with no result.
The engineer came today and checked everything which seems to be working well apart from somehow blocking my phones, but he was unable to help with "my equipment" so the problem is unresolved. The phones have worked on BT, Talk-Talk and Sky hubs over the past 5 years, and although now perhaps a bit old, functioned initially with Virgin. I don't think anything can have gone wrong with the phones or base unit, so assume the problem may be related to a Virgin update of some kind.

It would be helpful to know:
- if anyone else has had this sort of problem with VM?
- anything I could try to resolve it?
- of any other phones or items such as the Fritzbox that will definitely work with Virgin?

You could be on a congested part of the virgin network, can you setup a quality monitor https://www.thinkbroadband.com/broadband/monitoring/... and share a live graph.

Ian

You could try CSipSimple on an Android mobile phone to see how you get on, or maybe Linphone on Windows. Congestion could well be your problem as mentioned.

here is a link to the graph:
https://www.thinkbroadband.com/broadband/monitoring/...

But I think congestion is unlikely to be the problem - according to the engineer there are very few people using Virgin around here although the cable is in place. There is no variation according to time of day - it seems my phones can't access the server at any time now - although when first plugged in they could. I suspect is more likely to be related to a Virgin firewall or port blocking issue. But of course it is possible that my Gigaset system is faulty. I don't want to buy a new voip phone system if the issue lies with Virgin, but not sure how to tell...

It may be the jitter.

Ian

In reply to a post by Victoria16:

I don't want to buy a new voip phone system if the issue lies with Virgin, but not sure how to tell...

As suggested above, try a VOIP application on your PC - This will prove if it's a firewall/network issue or not?

Call the Gigaset help-desk - they are extremely helpful and know about most issues. They are not UK based but work 09:00 through to 20:00 and are on a UK number 020 3695 3111. I would guess it is related to a firewall of Virgin not routing traffic to specific locations.

I had a problem recently and wit me they worked through the whole set up.

Do you have all of your user details - ID, passwords, various server addresses &c? You can also get a short term temporary "trial" number and settings from many of the VOIP service providers - get a couple of those to try out too.

Maybe you could try a test using CSipSimple on a mobile phone.

It is a free download on Android.

Who is your VOIP service with? I'm using Gigaset C620 and C430 phones with N300IP base stations and Voipfone through Virgin Media and not had problems. I do have the Superhub running in modem mode though.

Dave

Mainly I use Voipfone, but I do also have Sipgate and A&A a/cs