marik - Errors are different, you won’t remember everything, but if you didn’t do anything yourself and everything worked, then it usually happens that there is a failure somewhere in the system. You just need to drive an error into Google and see what it is. It's the internet and stuff happens.

diana9 - Internal Server Error 5XX is a generic HTTP status code. You will see this 5XX code along with an internal server error message usually when you are on a website. This is the code that indicates an error on the page you are trying to access. You will see this message if there was a problem on the server side and the web page could not be retrieved. In most cases, the website server is the cause of the error. Thus, if you are a website visitor, you can see this error code on any device or browser. This error may be more serious for the website administrator or developer than for visitors. More information can be found here https://sitechecker.pro/site-audit-issues/amp-page-url-error-5xx/. For normal visitors, the error can manifest itself in different ways, as websites allow custom messages, but the error can always be identified using a code.

viktoria0 - You need to know the AMP status report. The top level of the report lists all the AMP error pages we've found on your site. They are grouped by problem type. By clicking on a particular line, you will see detailed information about the problem, such as which pages it was found on, what you need to do to solve it, and how to report the action you have taken to Google. Or contact SEO expert Sitechecker, who will explain everything in more detail and help you understand any situation.

arazun - To fix this you need to make sure that the <link rel="amphtml"> tag points to the correct (i.e. equivalent) AMP page and make sure that this page is fully accessible to both search engines and users