Hello,
There are no issues with any of the BoldGrid themes or plugins and HTTPS. The most common causes of HTTPS issues would be links on the page using HTTP instead of HTTPS or If you are using a CDN most of them will cache pages which can lead to issues if it was cached before you made the switch so that the CDN was displaying URLs that have not been updated or if you are using a CDN plugin it could have moved content to use a URL for the CDN that is not HTTPS or may have a conflicting name on the certificate. If you could provide us a link to your site so we can see what SSL error is showing or can give us a specific error message we can tell you what needs to be done to resolve your issue.
Best Regards,
KyleM