As Paulius commented, you need to figure out if your pool members are expecting encrypted traffic.
You can validate it via ssh with some curl commands from the F5 (curl -Ivvvk https://<PoolMember_IP>:8443), or by adding tcp, http and https health monitors to the pool and then view which ones pass or fail.
If the servers on the pool are setup to encrypt traffic on port 8443, you definitely need to add a server ssl profile to the virtual server.
If application traffic is http based at the application layer, you can also add an http profile to the virtual server and monitor the http request statistics for the pool. If the ssl handshake between the F5 (acting as client towards the pool members ssl encryption) and the pool members are working correctly, you should see the http requests stats on the pool increment with every hit to the virtual server.