Hello Sofy, if here are the screenshots.

This is with the option "Convert WordPress in wpForo" activated:

http://www.subirimagenes.com/imagen-cometo-9870560.html

And this option is disabled as advised by your partner:

http://www.subirimagenes.com/imagen-image1-9870561.html

As you will see in the first option, almost the entire width of the screen of the mobile is used and in the second, much side is wasted.

Hi @franricht,

The spaces on your website come from your WordPress Theme page design. This is not a wpForo issue, this is a theme issue. Please try to use this CSS code:  

div#et-main-area {
   width: 100% !important;
}

Don't forget to delete all caches before checking. 

Thanks, I've tried it and it's the same. Actually I tried almost everything and nothing works and did not try.

This is the CSS code that I already have:

@media (max-width: 980px) {
#et_mobile_nav_menu {
display: none;
}
}
@media (max-width: 620px) {
.et_header_style_centered #logo {
position: relative;
bottom: 40px;
max-height: 180px;
}
}
@media (min-width: 621px) and (max-width: 639px) {
.et_header_style_centered #logo {
position: relative;
bottom: 50px;
max-height: 140px;
}
}
@media (min-width: 640px) and (max-width: 980px) {
.et_header_style_centered #logo {
position: relative;
bottom: 20px;
max-height: 140px;
}
}
div#et-main-area {
width: 100% !important;
}

Hi @franricht,

Please remove all the custom CSS you inserted in website for this purpose. Once all your custom CSS is removed just leave your forum URL. Also please make sure the Turn WordPress to wpForo option is disable. Please never use that option for your forum.

Thanks Robert, but I need that code so that the image of the forum adapts to the different sizes of screens.

Why do not I use the Convert WordPress option to wpForo?

With that option I can solve the problems and if I want to publish a page I can do it in "Exclude page URLs (one URL per line)"