You are unable to hear anyone on the phone, or your call sounds distorted or crackly.
There can be a few troubleshooting steps for this, we have listed the most common below:
Checking your cables
One important first step is to ensure that your phone and any headsets are plugged into the correct ports. You may have a loose cable in either your phone or the headset which may be causing the issues on your phone.
Reconnect the headset
If you are using a USB or wired headset you may need to reconnect this device. Unplug it from your phone and wait for about ten seconds before plugging this back in. Allow a moment for your phone to finalise the connection and place a test call to see if this is now working as expected.
Disable SIP ALG
One issue that could be affecting your phones is a setting on your router called SIP ALG. This setting is a tool that your router uses to inspect SIP messages used in VoIP communications and transforms these messages which may result in some issues on the network. We have a guide here which goes over a few common routers and the steps to switch this off.
If the above steps did not resolve your issue, you can raise a case with our team by clicking here. We may verify that you have completed the above steps, so don't forget to try!