Hi Amioline,
Greetings, as I viewed your project description, I can fix the 500 error, make your website live again as I’m having an expertise, so, it wouldn't take much time to execute the results.
Holding an experience of 7 years in UX designing though, I have work experience in HTML5, CSS3, Bootstrap, Material Design, Js, jQuery, Angular Js WordPress, Shopify, OpenCart development etc.
I’d like to request you to reply back so that we can discuss your requirements in detail till then Stay awesome & let’s expand.
Thanks & Best Regards
Amit J.