We are happy to share with the community our FREE installer for CEP extensions for Adobe After Effects and Premiere Pro. It will work with any ZXP extension, it does not have to be one you got from us. It has a fallback custom install option that should work in cases where other installers (including Adobe's own installer) fail. So if you have been unable to install a ZXP extension on you system please give our installer a try. It has a super friendly and easy to use drag and drop on Mac and double-click on Window.
**Please note that the issue with macOS High Sierra has been fixed. If you still have any issues, please open a support ticket