If you can post (or email firstname.lastname@example.org) your .hype document, that would be useful.
In v3.6 we changed to using a tool with better colors/filesize, but sometimes an export can take a ridiculously long time in the last step (and I guess potentially forever if you are seeing that!).
There is a method to use the older GIF export, should you ever hit issues via this terminal command:
defaults write com.tumult.Hype2 AnimatedGIFEngine Apple
For anyone experiencing issues, we'd appreciate a bug report via Help > Report an Issue… before changing to this method.
To change back, you can use:
defaults delete com.tumult.Hype2 AnimatedGIFEngine