Cache tester fails

When I do the test it comes back as a fail, however when I check the time stamp in the source code of the page and open another one to compare they both have the same time stamp, do I need to do anything?

“2. Enable logging on the Debug page here. That should help you track down the problem.
3. You should check Page 1 and Page 2 above for errors. Your local server configuration may not allow your website to access itself.”

You lost me there. I understand that the last tab is for debugging but I don’t know how to use that tab or what to do with the information provided.

Thanks in advance.

https://ww.wp.xz.cn/plugins/wp-super-cache/