Web console lost connection

Hi guys!
We have a problem with our cluster that web console lost connection sometimes.
For example if web console fails on one node, I try to open it on another, but it also fails.
Why does it happen? How does web console work?
Is there some master node that collect info from all nodes in cluster?

Can you provide bit more info - version, # of nodes in cluster, was rebalance operation running, etc. You should be able collect log from any node in the cluster using the command-line - cbcollect_info or from UI.