Interaction Server Error - Client is not logged In

Hi

I have two instances of my application which is logged in by two users.
Both the agents are logged in. However, when agent1 trying to make a conference of one interaction, he is getting Client is not logged in.

Sometimes i’m also getting Place is not logged in

I’m using Genesys Interaction Server 7.1 and accessing through Platform SDK .NET.

What might be the cause of the error?