No inbound calls from registered provider

[grenadine]

Hello,

I have voxalot registered to a provider 3starsnet which has my DID.

C450IP <----> voxalot <----> 3starsnet.com (DID)

This has been working fine for weeks, since today I am not receiving calls.

Callers to my DID get "the person at extension .. is not available"
Callers to my voxalot number get through and all works fine.

On the voxalot web I can see that 3starsnet is active and registered.
I tried unregistering and re-registering, no change.

On the call log of 3starsnet I can see the failing incoming call
On the call log of voxalot I cannot see it

What is happening and how can I fix this?

thanks