Error 500 on fully PHP pages

website URL

Error Message

Error 500

Other Information

This error occurs only when I enter the page where all the codes are php. For instance when trying to login to the website, signing up or sending messages.

I have checked the code on my local server but there where no errors all pages worked perfectly.
Please need help.

Help yourself

This is what I see


Yeh, the website is created for mobile. Please, just reduce the viewport of your browser to 320px width so u can see the site properly.

there are some tips here for making your website responsive to device screen size if you wish

w3schools responsive