Peplink Balance 310 Port 110 block

I don’t understand it worked a long time and now i can’t get my email on my Macbook Mail client, the port 110 seem to be blocked but Inbound Access Services UPnP / NAT-PMP are enable. Please can someone help me ?

Please help to open ticket and attached the network diagram to show how the mail server, Macbook were connected to Balance 310.