No voice on incoming calls.

[Nle]

Just started having this issue in the last couple of days, i.e. incoming calls can't hear me although I can hear the caller just fine.

Outgoing calls work just fine.

Rebooting the Grandstream didn't help.

I've opened a support ticket.

Exact same problem. Incoming calls don't work (other party cannot hear me).
Setup: Cable Modem -> Router (forwarding enabled) -> Grand Stream 502

My settings do NOT block any type of call