Errors on my website

I have recently created an e-commerce website using coding that I learned from your site. However, I am currently facing an issue where users of the website are encountering a 404 error message after spending a few minutes on the website page. I am not sure if this is an error caused by my coding, but I would like to get a better understanding of what might be causing this issue. I am attaching a link to one of the pages on my website where this problem is occurring, https://justelegance.de/collections/iphone-13-hullen and I would greatly appreciate it if someone could take a look and explain to me why this is happening. I want to ensure that my website is functioning properly and that users are able to navigate it without any issues. I want to make sure that I didn't make any mistakes during the coding process that might be causing this error to occur.