It's already been some time that Tixati has a problem with UDP trackers, but now after upgrading the version it's been worse since I have no idea how to change the settings. I get this message about some trackers:
"UDP trackers disabled in settings"
But it doesn't seem like they are disabled. What can I do? It's getting quite frustrating.

try going to settings-transfers-trackers
make sure the option 'Allow UDP tracker connections' is selected.

Thank you!!!!! I feel stupid for nor seeing that myself haha
Now I get the error message I'm used to of: "Could not listen for incoming connections"
I still have no idea how to solve that but at least now I can enable/disable UDP when I need to.