This is resulting from an outbound connection to Equifax's new TLS 1.2-enabled URL.

Background: Servers: Windows 2012 R2, .NET 4.6.2, all TLS 1.x Enabled in Test, Stage and Production tiers per this. IIS configurations match between servers (app pools/code except tier-specific configurations/IIS settings.)

Servers are load balanced via Citrix Netscaler, but this site uses Port 80/HTTP, no HTTPS configuration.

Both tiers use the same Equifax URL, but with tier-specific credentials.

The Situation: Prod will not communicate with their site, we get the opening error.

Our stage environment has no problem communicating.

What we have done: - Validated TLS reg settings match - Swapped the prod web.config to the Stage server and the communication worked, so it seems unlikely that it is a web.config issue in production. - Validated .NET versions - Checked LSA fips reg setting (set to 0) - checked for wonky updates known to cause issues

We are going to setup a network trace, but for the moment we are at a bit of a loss. I would appreciate any insights as to what I might be missing.