SEP client VPN Connection Breaking every four hour

Hi Support,

We need help in SEP client. I have a SEP 12.1 RU1 client machine. I am using VPN connection on SEP client to connect client to other location. But my VPN connection disconnect every four hours. I had also check network traffic and packet log but there is not show any block information. After that i had also disabled SEP client firewall and exculde local IP address on intrusen prevesion. But the problem still not resolved.

If I removed SEP from client then VPN is working fine.................Please help me.....