I could be wrong, but it appears that the stream games by IDs endpoint (https://lichess.org/api#tag/Games/operation/gamesByIds) might be down? I'm not getting any game responses when using python requests, or via curl... example: curl -d "PUqrSjvD,qWUqwoL2" -X POST https://lichess.org/api/stream/games/uniQU3AppNam3-trb123
From reading the docs, I should be receiving a response immediately on stream start, and also on game completion and I'm not receiving it on either.
I can successfully stream a similar endpoint (api/stream/games-by-users) without issue, so I believe my syntax is correct.
Most likely by the time someone reads this, those game IDs listed will be finished so you'd have to test with different game IDs which are actively being played. I've also tried with just one game, multiple unique (or what I assume would be) stream IDs, etc.