The Proxy event Log is showing  a large volume of SSL related errors containing the following:

SSL3_READ_BYTES:sslv3 alert certificate unknown(0) SEVERE_ERROR

This error refers the inability of the proxy to find an SSL keyring in its configuration that is being referenced somewhere else in the configuration, like Policy, for example.

The solution for this issue is to go through the configuration looking for keyring references that do not line up with any existing keyrings, then modify the configuration so that the references are in tact.