Sipstation module "The server is currently not responding"

See this previous post, as this may be relevant to your issue:
In short, you can try the following:

  1. Make sure you External IP matches what you’re registering with SIPStations
  2. If you have more than one ISP, make sure your external IP matches your Asterisk settings
  3. Reset your token key in the SIPstation portal, as possible the settings may be wrong

If you’re a current SIPstation customer, I’m pretty sure you can call support and they will help you, as in my situation, they helped in about 20 mins.