Reply To: Port Forwarding stopped working

IF your IP-address is defined by DHCP, it is possible that after some longer timeout a different IP-address could be assigned to your computer.
In that case check if your router can make a fixed IP-address assignment to your computer which is often presented by name but the assignment is made to the MAC-address of your network interface which is a worldwide unique address.

It might also be that on the SOundJack stage for some reason the IP-address of your WLAN interface is selected. In that case select the IP-address of your LAN-interface there. If it is not present check the LAN connection and reload the stage. Then select the LAN-IP-address on the reloaded stage.

I have no experience beyond Mac OS 10.14, so if it is a BigSur-problem someone else need to help you.
It would be nice for others reading this if you could write back here if my hints (and which one) helped with your problem.