@whimpers It seems the root line is missing.
But what should the root be
The folder where your index.html file is located. It often starts with /var/www/... Some people use /srv/mydomain/www or other places.
Still getting the same error
There is another possible problem:
@whimpers said in How to put the Forums in a directory instead of homepage:
try_files $uri.html $uri/ /index.html;
It looks like this line can cause that error if /index.html can't be accessed, maybe because of permission or owner problems, if the root line is correct.
Since index.html is already in index, you can try something simpler like:
try_files $uri $uri/ =404;
This will give a 404 not found until you fix the permissions problem. Try chmod 777 index.html (from its folder) to see if this is the case. Then change the owner (probably a user sharing a group with the www-data user mentioned in nginx.conf) to be able to use the safer 664.
It works! Thanks!
Glad to read that. 
Awesome job @Juan-G ! Glad to see people helping each other out on the forum 
