I'm using Ubuntu 14.04 and I keep it up to date. During last month it started having difficulties connecting my campus network (wired eduroam network), it keeps asking for authentication and connects after entering my password couple of times, sometimes connects at first, but two times I had to continuously restart network manager and enter my password for two hours to connect. All this time no other computer has experienced any trouble and internet works fine so I assume it's not a network problem. The password is correct and no other (other than regular updating) changes were made to computer. Thanks in advance!
It seems today it was actually problem with the network because other computers also experienced similar error. I'm gonna mark question as solved but will write again if this condition continues. Cheers!