Sometimes you can experience plugin issues that seem to be caused by Really Simple SSL. What most people forget, is that when you activate Really Simple SSL, you also force SSL (which is not the same). In some cases your site being on SSL can also cause the issue.
When you activate the SSL plugin, three things happen:
- siteurl and homeurl are changed to https
- 301 redirect is added
- Mixed content fixer is activated
An easy way to debug Really Simple SSL is to enable the safe mode. Follow the steps in this article to track down your issue.