Hello- I just upgraded a test site from 2 to 3 and the ask a question isn't working. When you click on the ask a question button, the page refreshes but there's no popup. I didn't receive any errors when I did the upgrade. Everything else seems to be working fine.
Are you using a 3rd party Joomla! template? If yes, then you need to contact the respective template developer for this issue.
Thank you!