We had problems with the linkus app, when it is used in another network than the local network e.g. 4G network. A solution for this is to use another SIP port than the standard 5060 UDP port, because 5060 is mostly blocked in 4G network.
How to do this:
- change in Settings/SIP/General/UDP port 5060 to i.e. 8888
All local phones have to register to that new port
- change in Settings/SIP general/NAT/Local IP adress port 5060 to 8888
- You have to change this in the router as well
- Configure the linkus app
Linkus app works now fine, because it use another port that not is blocked in 4G system