If http://127.0.0.1:45365/mapData returns null for everything even in raid then it's not a firewall issue. Some other mod must be causing a conflict - most likely a client mod. You can see if the same issue happens without any client mods to confirm it. It is confirmed that these mods caus conflicts, but it might also be some other mod entirely:
Enable All Quest Items
Helicopter Crash Sites
Boop's Quest Zone API
Damn okay I have Boop's Quest Zone API, so that's gotta be it. Is there any sort of workaround or can I just simply not have both installed?
Edit: Deleted Boop's Quest Zone API and the trader that required it. Which immediately fixed my issue. Thank you!