hostname not found

[flexium]

I am using utorrent 2.0 on window 7 with window's firewall and NOD32 antivirus both OFF.

I was downloading fine and one day none of my torrent can find any of their trackers anymore. They either say "hostname not found" or "offline(time out)". DHT is always at "waiting for announce..".

I am sure the torrents are alive and has many seeds. So it must be my end that's going wrong.

I have also tried randomizing port but that has no effect on anything.

I think something is blocking the connection for utorrent but i don't know what it is. What can I do?

Thank you

Edit: Shouldn't be router because i was okay before. In fact, i didn't change anything and it just stopped connecting to tracters.