Originally Posted by JJKom
This might be just shot-in-the-dark but I have noticed similar problem in pure win network and new router.
For some reason that router is limiting access to only those IPs that are in DHCP range, in this case those Amiga IPs are outside it.
No matter if connection was wireless or wired, that router did not "see" or allow traffic with IPs outside its DHCP range.
Fix was to use only IPs that are inside, in this case set router to give always same IP to those Amigas and use DHCP with them.
Interesting, gives me an idea.
If JJKom is right, a possible fix could be to configure the Amiga hosts within the DHCP server IP range as static (fixed IP address), where you enter the MAC address and IP address for each Amiga host, most routers can handle this within the DHCP part of the configuration.
OK, I missed the "fix" part of JJKom's post, same suggestion using different words.