Navigate to the web control panel for your server. Click edit on the extension you need SRTP on.

Check “Use Encryption”. Save the settings.

Navigate to the web control panel for your Yealink phone.

Click on the Account Tab, Click on Advanced. Find the setting for “RTP Encryption(SRTP)” and change to Compulsory. Save the settings.

Test the new settings by dialling *60 from the extension to listen to hold music. If you get the message “Not acceptable here” then check again that you have changed the above settings correctly.