VOIP invalid username

[#1]

Is there a problem with Plustalk today?
When I start XLite I get an invalid user name message.  I don't use it very much, and haven't done so for a few weeks I think, but went to use it today and got this message.
John

[#2]

I just tested mine and I'm connecting to it fine, although my first attempt timed out.

[#3]

Hi
I just had another go.  I have used the VOIP loads of times.  When I set it up, the only way to get it to work was using Plustalk as the user name, but when I just checked the user guide again, it says to use my SIP ID as the user name and authorisation name.  I've changed the set up to this and it works.  I can only assume that something has changed at the Plusnet end.