http error on my site

I'm experiencing an issue with my website and I need help resolving it. Specifically, I'm getting a "500 Page Not Found" error when visitors try to access my product page. This has been happening for a few days now and I have not made any recent changes or updates to my website that could be causing this issue. I'm looking for an experienced website developer who can resolve the error and help keep customers from being unable to view my product page.
I want to find someone that I can work with long-term, a good partner.
Thank you for your time!