Youtube videos not showing after adding HTTPS
I'm using Vanilla 18.104.22.168 and I've just added a certificate via my ISP to enable HTTPS for the site for ResetTheNet. However, now YouTube videos don't show in the comments.
The space gets resizes (see example https://makegamessa.com/discussion/2127/netprophet-videos-are-now-up#Item_1) but there's no video.
I've checked that the YouTube links are HTTPS as well.
What can I do to resolve this?