App Control Server: Palo Alto Wildfire connector and integration no longer working

Products

• Carbon Black App Control (formerly Cb Protection)

Issue/Introduction

• Reporter log shows: WARN WildFireAdapter - System.Net.ProtocolViolationException: You must write ContentLength bytes to the request stream before calling [Begin]GetResponse. 
• Reporter log shows: WARN WildFireAdapter - System.Net.WebException: The operation has timed out 
• TLS 1.2 is not enabled on the App Control Server

Environment

• App Control Server: 8.0, 8.1.X
• Palo Alto WildFire Connector: Cloud

Cause

Palo Alto WildFire Cloud service appears to be using TLS 1.2

Resolution

• Enable TLS 1.2 on the App Control Server
• Ensure .NET is setup to utilize TLS 1.2 as per this