php function does not work on hosting

hi, I run my php code on xampp localhost is works. No problem sending information to database. But running on host my form I currently getting the issue 'www.bigrafi.com.tr is currently unable to process this request' HTTP ERROR 500 etc. By the way, I'm submitting my form from an html page, that wouldn't be a problem, would it? While the page is being refreshed, I think there may be an article like your message has been sent. is this good or it could be a better suggestion