Exchange POP Session Persistence Profile

Hi.

In our BIG IP (LTM), we have MICROSOFT EXCHANGE 2016 iApp with two servers in production, one server connections is so much higher than other, based on connection i found that one of our application servers always is routed to the one server. Also if found that Session Persistence Profile for POP protocol is "source address affinity persistence".So in situation like this what should we do to balance the connections between servers?