backslash error and NGINX

[blacksrv]

Hi, I'm having some issues with PW after a NGINX error, I'll try to elaborate:

1) My nginx site conf file went corrupt.

2) try to recreate it using: https://processwire.com/talk/topic/275-processwire-on-nginx/ 

3) All my urls are accesible using '/' or without it.

4) I have urls that doesn't work without the / at the end, the url is dynamic (I check for the segments)

Ex:  
"www.url.com/something/countries/usa" works!
"www.url.com/something/countries/usa/" works!
"www.url.com/something/countries/mexico/" works!
"www.url.com/something/countries/mexico" doesn't work

I assume it has something to do with my nginx, it only happens with the same country, in fact if you use a country that doesn't exist it just redirect you to the main url, but in 'mexico' case it just return a 404. 

Any ideas???

edit: something I forgot I testing adding it a backslash to all urls but the backend has some troubles when it comes to saving.

[blacksrv]

anyone?