ICA session gets disconnected after 2-4 minutes of inactivity and this occurs only through NetScaler Gateway.
ICA session works without disconnection while connecting directly through StoreFront or Web Interface.
Complete the following steps to resolve the issue:
Verify the client idle time-out in gateway session policy.
Enable session reliability on StoreFront to help in case of disconnect issue.
Ticket mismatch occurs at the time of reconnection after idle time.