Port forwarding connection timed out 110 error and 111 error when I turn the firewall off

[earthlight 0]

port forwarding has been working completely fine since I started using airvpn and yesterday it suddenly stopped working while I was trying to connect a friend to my game server in Hytale (it worked fine with this game before I don't believe it's the cause). canyouseemee says iIcan't be found. I have not been able to fix it. I've looked at countless forum posts and no one seems to have had my exact issue. Went to bed and thought maybe it'll fix itself, nope.

I usually like to fix these things myself but after turning my firewall off, checking if any permissions changed, checking my airvpn settings, making a NEW port, resetting my router as well as turning it off and on a bunch, I don't know what else to try  Like I mentioned in the title the error changed to 111 when I turned my firewall off. 

Edit: I forgot to mention UPnP is actually turned on on my Router and working fine when I turn my VPN off. 

Any help would be appreciated thank you!

Edited ... by earthlight

[Staff 10433]

@earthlight

Hello!
 

2 hours ago, earthlight said:

Like I mentioned in the title the error changed to 111 when I turned my firewall off. 

Possible explanation: the listening service does not listen to the VPN interface or is not running.
More in details: when the firewall is on, the test packet is silently dropped, so the port tester does not receive a reply and throws error 110 (timeout). When the firewall is off, the attempted connection by the port tester does not time out anymore because the packet is not silently dropped, but the relative connection is reset via TCP RST because the final VPN interface port does not exist and the device kernel is configured to reset connection to non-existing ports.
 

Quote

I forgot to mention UPnP is actually turned on on my Router and working fine when I turn my VPN off. 

This is consistent with the previous description and explanation. If UPnP works fine when the VPN is off, then it is active on the listening software too. Due to how UPnP works, the listening software will bind to the physical network interface and not to the VPN interface, causing the problem. Please note that if Network Lock is not active you will also suffer traffic leaks outside the VPN tunnel because of UPnP. Please keep UPnP disabled at least on the settings of the listening software. Consider to disable it at router level too as a pre-emptive safety measure if it is not strictly necessary.

A checklist you can consider to follow:
https://airvpn.org/forums/topic/66388-port-forwarding/?do=findComment&comment=243305

Kind regards