The I/O operation has been aborted because of either a thread exit or an application request.

[Sonja_Bauernfeind]

The Qlik Sense proxy cannot be accessed via .NET code.

A 403 forbidden error is returned.

The logs indicate:

The I/O operation has been aborted because of either a thread exit or an application request.

Environment:

Qlik Sense Enterprise on Windows 

Cause:

The .NET code was defaulting to a disabled TLS version. 

Example: TLS 1.0 and 1.1 are disabled, but not 1.2. The .NET code may default to 1.0, which is disabled. 

Resolution:

Specify in the .NET code System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 to target TLS 1.2, which should enable the API call to work correctly. The equivalent can be used in Powershell by adding [Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12 to the calling script.