Just tried to load the mod with mod caching off. Had no problems, maybe it was a temporary thing.

There is a chance this may be an issue with linux tts. I manually downloaded and imported https://lithi.io/g/tts/Secret.Hitler/placards/placard.chancellor.compcoll.obj and it worked perfectly.
You also have to time import with the spawn or the chancellor card will get stuck in the table lol
I will have to report this on the main support page, as I do not think this has anything to do with your game mod.
Great work making such a beautiful tts mod btw. This could be a dlc. I'd buy it!

I also have this issue; I'm on linux btw.

Couldn't it be possible to change to http? Would there be any disadvantage?

That is a question for Lithium to answer, but for now i have updated the backup file on this page.

This issue is being investigated.

Hey, I get the same error under Ubuntu 16.04. I tried the backup file but the moment someone picks a cardset from one of the boxes an import dialog appears and the mentioned ssl errors show up again

As it turns out, Tabletop Simulator on Linux & OSX are attempting to fetch the links via SSLv3, which has exploits tied to it, so it is generally disabled on most networks, including mine (lithi.io, hosting the assets to Secret Hitler). So the best you can do is download the Secret Hitler mod backup listed on the front page and follow the instructions regarding that on the mod page.

If this issue is affecting you then PLEASE report it to Berserk Games via their forums or comment on my thread in the Technical Support forum here:

http://www.berserk-games.com/forums/showthread.php?2628-Linux-amp-OSX-make-requests-for-assets-via-SSLv3-and-fail

A game that relies on external hosting of assets should not have issues like this.