I had the same thing happen to me, but in my case, I disconnected the connection once on the Twitch site and tried again, and it connected to Twitch
Viewing post in Twitch Integrated Throwing System comments
Hello! Have you tried using the newest version? This issue has been resolved and has been an issue due to Twitch updating their API. So the old version of TITS was using old API features, which have now been migrated over to the new API. If there are still issues, please post your issue on the official discord!
Hello! I did manage to resolve my issue once I went to the Discord. I ended up installing the launcher so then it could be automatically updated whenever I run TITS.
However, initially when I was trying to redownload/reinstall the update, it wouldn’t let me since it claimed that “there were no compatible versions”, though I believe this was an issue with the Itch.io desktop app since it finally worked once I used the website.