Deluge 2.0.3 Windows - Tracker Status Questions

[silekonn]

Several trackers are erratic or showing non-functional status. An explanation or resolution to these would be appreciated. They include:
Error: No such host is known
on part of the torrents from the same tracker addresses.
Error: unsupported URL protocol
on all ubuntu.com torrents
Error: No connection could be made because the target machine actively refused it

TIA