This isn't a tutorial but more like a check this if you can't connect to trackers.
I noticed that I wasn't able to connect to certain trackers, after digging a little deeper there was a reoccuring pattern of the tracker using ssl/https. There is a known bug in Ubuntu,
libgnutls26 2.12.14 breaks SSL tracker support in Transmission ( In order to fix this, just update that libgnutls package.
In a terminal:

sudo dpkg -i libgnutls26_2.12.20-2_i386.deb
sudo dpkg -i libgnutls26-dbg_2.12.20-2_i386.deb

sudo reboot
You probably don't need the debug utilities but I grabbed them anyway.
I hope this helps anyone who is stumped on why they can connect to certain trackers but not others using Ubuntu and Transmission.