I can’t work out how to ask a support question - the only place I could find a “new topic” button was in Site Feedback.
I have a question about LibreOffice Impress and I have no idea how to post one.
Go to your language category (i.e., English) and choose + New Topic.
EDIT:
No need to choose a category:
EDIT 2:
Seem solved. See: My PC reboots whenever I try to run a slideshow with embedded mp4 videos