A) There are a lot of potential hiccups with trying to get a new IP: - Some ISPs assign statically (odd, but true) meaning you will always get the same public

A) There are a lot of potential hiccups with trying to get a new IP: - Some ISPs assign statically (odd, but true) meaning you will always get the same public IP - The DHCP lease time is different for many ISPs: 5min to weeks, meaning you’d have to be offline for at least that long in order to be assigned a new IP when connecting - Some ISPs lease it to the modem and not the router or anything internal (does not apply to what you said, but another tactic: changing the MAC address) B) OP asked how to investigate. If getting a new IP dodges the issue and it doesn’t happen again, then there’s basically zero chance that the actual cause will be known