Scenario:
I am using wordpress for my blog. I have registered my blog in disqus.com. I just installed the ‘Disqus Comment System’ wordpress plugin in my blog. Now, when I try to access my blog’s RSS Feed, I get error saying “Closing Tag Mismatch” and the RSS Feed is not displayed properly. The feed crashes.
Cause and Solution:
There might be different causes for this type of problem.
1) This may be caused by your current theme or a plugin. You can test this by temporarily reverting to the WordPress Classic theme. If that doesn’t fix it, then try disabling all plugins except for Disqus. Then, check your Feed if it works properly.
2) Try putting a check in the “Comment Counts” checkbox under Advanced Options in the Disqus plugin. Disqus itself has written this note:- (NOTE: Check this if you have problems with the comment count displays including: not showing on permalinks, broken featured image carousels, or longer-than-usual homepage load times)
The second option helped to solve the RSS Feed issue with my blog.
Hope this helps. Thanks.