@Kotton 

 

In general, if you want to get rid of UPnP, you should do that on both your router and Synollogy NAS.

On your router disable UPnP an manually set up pott-forwarding.

On Synology NAS:

Access the Control Panel in DSM. 
Navigate to Security > Firewall. 
Create firewall rules to allow the necessary incoming connections from the internet to your NAS on the specific ports you have forwarded.

 

 

if upnp works but manual port forwarding does not that usually means the forwarding rules are correct but something upstream is blocking or overriding them first thing to check is if your isp gives you a real public ipv4 address or if you are behind cgnat because if it’s cgnat no manual rules will work only upnp tricks sometimes get through also note that ports 80 and 443 are often blocked or filtered by many isps to prevent customers from hosting web servers so even with the rule in place the port checkers will always show closed to confirm try forwarding a high random port like 50000 to your nas and test it externally if that works then the issue is not the router but your isp policy on 80/443 if high ports also fail then check if the ax55 wan is in router mode with a real public ip if your main modem is also routing you may have double nat and in that case you need to either enable bridge mode on the isp modem or set up dmz towards the ax55

  @Kotton 

 

Would you mind sharing the solution that solved your issue with the community, so more people can benefit from it.