I just got a installation request from you. It seems that you don't realize that https is a protocol, and Chevereto either auto-detect https or you force https for your links. That's all, Chevereto doesn't handle the SSL cert of your website. Https won't work as expected unless a valid SSL cert is configured in your server.
Keep in mind that Chevereto is a piece of software that runs on a server, it is not a software running your server. Please don't mix stuff and note the difference.
Your forced https is screaming all the problems derivative of trying to fool the web browser with a non compliant https website. A re-install won't fix these issues.
Chevereto detects when https is working properly and in that situation it turns all links into https. If you force https, is understood that you are aware of the fact that the links will be printed as https, but that doesn't mean that the web browser won't panic for an invalid https connection.
Disable forced https until you get true https there.