We are having a strange issue with our Skype for Business.
Its been running just fine for sometime now but we have some external clients that are having an issue with our Skype ids.
What's happening is that we can send them a skype message and they receive it, but when the try to reply back to us, it eventually times out for them, and we don't get their reply.
Also when they bring up their list of other clients including ours, ours show up as status, Presence Unknown
Does anyone know what I can check to see why our IDs would be appearing to them as Presence Unknown?