I’ve tested the plugin on an archive page using Twenty Sixteen. I haven’t been able to duplicate an error 500. Error 500 can be difficult to diagnose.
I wonder if the issue might be with the gravatar. Are you using gravatars? Does the email link to an actual gravatar? Is the gravatar showing up on single posts? If not, does your host block external web traffic? Sometimes hosts block everything except for google. Make sure that it doesn’t block wordpress.com.
If not, I need a little more information. Which browser were you using? On the specific page were there more than one post by guest authors? Are any of the posts on the archive pages using plugins that use ajax? Perhaps you can email the author details at [email protected].
This might not be worth your time, but you can try this.
There are advanced ways to diagnose these errors. If you go into the inspector, click on the network tab, and in that tab, click on xhr and then refresh the page. You should see a list of status. Find the one that says 500 to see exactly where it occurred.
Let me know. Feel free to email me directly.
