We last had a system admin that installed OpenSIP(which can be googled to fnd out more) onto our Linux server. Therefore, 3 usernames with their corresponding passwords have been created, along with a database. It is able to make calls with these user accounts or credentials, - but when I pick up call, it mostly gets disconnected. - On the rare occasions that the person called to could finally pick up the calls, there was no voice heard. So, absence of voice between the callers. - In addition, video call was nor even initiating. - Finally, Chat is also not working. One can check the sip confic file to realise it.
- A necessary other step: To enable some codec like G722, G729, PCMA, PCMU and some video and audio codec too.