Thanks. That's why I said "supposed to".
I did some research on the XF support forums, where there have been reports of degraded ability to embed Instagram. This October 2020 article was linked by a member as a possible explanation:
Facebook and Instagram are dropping support for embedded content on WordPress sites starting October 24.
www.searchenginejournal.com
An XF developer said in response: "[The problem] is related to the link posted. Essentially it's not possible for us to include Instagram embed support any longer. 2.2.1 has some changes to handle this a bit more gracefully (and the next release may have further changes) but unfortunately there's not much we can do to support this out of the box."
If you can copy an Instagram link, you may still be able to just paste it into the text box here. That procedure may end up at least with a link to Instagram.
I'd encourage IG and FB members to keep experimenting with IG and FB pictures and videos and report back what works or not. This is a group trip we're on.
(BTW, I just used an "unfurling" link to that article. I'll tell how to use Unfurling URLs in the
Features: Help and How-To Running Thread.)