Huh...you're running a Java SDK on your router!?!?
Since you never provide information on this, it's unclear why you even mentioned the IPs...but if your routes are incorrect, that could cause an issue. Additionally, there's a setting that if the inbound packet enters an interface that the router cannot reply with due to an invalid or absent route using that interface - the packet is dropped.
What routes did you add (routes are rarely needed for such connections)?
Where is this 192.168.15.0/24 network..is this WAN, LAN or the WG interface???
Also, I'm completely unclear on what you mean by a /48 and /60
Please specify the location of these networks - they cannot be gleaned from the information already provided
You don't mention settings on the affected machines (i.e. Windows)
Did you alter any setting that affects ports 61000 or greater???
Have you returned the settings back to normal???
Your wording seem to imply you're quite aware of those settings...
I think you should begin with a default config, then re-install Wireguard, then re config the routes.
On a diffrent computer on the LAN that is running the wireguard "server", which is why there are static routes
I have not touched any settings on those computers, they are left at defaults
Wireguard is not on the router. last time this happened i did try removing the routes. Also if the routes where incorrect all traffic would be affected
After reading all this thread, my humble first impression is that this could be a NAT issue.
When a client tries to open a connection with an external server, the router must open a connection from its WAN interface, and route/NAT the traffic between the client and the server. For some reason, it looks like the router is assigning a high port to that outgoing connection, and then rejecting the response packets from the server.
That NAT64 feature, and the local port range parameter, could both be related. Perhaps the NAT helper is choosing a port that should be reserved for other purposes, and hence the blocking on the response packets.
