Port 80 always in use problem - empty response

[marcelo1337]

I have a problem that port 80 gets occpied by somethig  on my firewall and it seems not to be the webgui.
i always get empty response from port 80.
No matter what i do port 80 is occupied.
i tryed to disable http redirect for the webui.
set the webui port to 8443.
and also set the webui protocol to http.

i would like to install the nginx plugin and use port 80 by nginx. the weird thing is that if i disable http redirect nginx can bind on port 80 but still somehing occupies in and always send a empty response.

i tried to set the web ui to http and port 80 and then i cloudn't access anymore since i get an empty response. all the time. what could this be and how can i free port 80?

[marcelo1337]

PS: port 80 seems only to be bound to the wan address. Also i change the web ui to LAN only it does not helpt.