Twitter Onebox preview not working anymore on my discourse

Hi all,

For a few days, twitter links do not create onebox anymore on our discourse install (v2.4.5 with 2 plugins: spoiler-alert and whos-online).
Old onebox are still working but new ones seem to be unable to retrieve information from twitter and they generate this:

But this should generate this:

I would greatly appreciate if someone can guide me on where I should start looking for fixing this.

Have you tried searching? This is dupe topic, see here: Twitter embeds have broken