Forum Discussion
Can you navigate to:
https://lyncweb.domain.org/CertProv/CertProvisioningservice.svc https://lyncpool.domain.org/CertProv/CertProvisioningservice.svc
Both should prompt for credentials. If this fails, and you're not using the BigIP as an outbound gateway for the web servers, make sure SNAT is enabled and using available IPs. The connection closed is not something that should be happening unless the BigIP cannot hit the web server properly.
Technically the reverse proxy is just a SNAT port forward and can even be run as a fast L4 with no proxy functionality. Also, remember to make sure the internal node for the reverse proxy is set to port 4443 and not 443. This is how Lync knows the difference between external and internal connections.
Else, you may need to wireshark on the web server and BigIP to see where the connection is actually going.