I have v15 3cx on windows all the updates loaded, yealink phones provisioned. sometimes the 3cx client for windows when in CTI mode cannot control the deskphone.
Similar cases have been covered several times in these forums before however the interesting thing about your issue is that you say "sometimes". In a lot of cases it is network related (VLAN's blocking between Data and Voice networks for example) however if you say that it does work at times it would not be this.
That being said a network description would be good if you are doing anything out of the ordinary (phone and Softclient outside of the local LAN and flat network).
Also please try checking the machine the Softphone is running on:
* You are on a supported version (Windows 7, 8, 8.1 or 10)
* You say all the updates but have you checked your .NET Framework as well (.Net 4.5.2).
* No windows firewall or anti-virus on the local machine blocking.
Also worth checking your Yealink phone is on the latest "supported" firmware for 3CX.
I have v15 3cx on windows all the updates loaded, yealink phones provisioned. sometimes the 3cx client for windows when in CTI mode cannot control the deskphone.
Hi
When ever we have had this problem, the simple solution was add the ip address of the desk phone to the Proxy Exceptions list in the PC's internet options (Internet Options - Connections - LAN Settings - Exceptions)
This has always solved the problem for us.
