Adobe AUSST - Initial download fails with Network error

Server: Windows Server 2016

AdobeUpdateServerSetupTool.exe: 4.2.0.8

Proxy Port 8080

AdobeUpdateServerSetupTool.exe --root="C:\inetpub\wwwroot\Adobe" --fresh --proxyusername=<username> --proxypassword=<Password>

or

AdobeUpdateServerSetupTool.exe --root="C:\inetpub\wwwroot\Adobe" --fresh

The initial download fails with Network error

AdobeUpdateServerSetupTool returned wird code: 4

C:\Users\<username>\AppData\Local\Temp\AdobeUpdateServerSetupTool.log

01/02/18 08:46:13:225 | [INFO] |  | AAMEE | Utilities | AUSST |  |  | 6540 | ************************* START Adobe Update Server Setup *************************

01/02/18 08:46:13:226 | [INFO] |  | AAMEE | Utilities | AUSST |  |  | 6540 | Rootpath = C:\inetpub\wwwroot\Adobe

01/02/18 08:46:13:226 | [INFO] |  | AAMEE | Utilities | AUSST |  |  | 6540 | Fresh is true.

01/02/18 08:46:13:227 | [INFO] |  | AAMEE | Utilities | AUSST |  |  | 6540 | Username = <username>

01/02/18 08:46:13:227 | [INFO] |  | AAMEE | Utilities | AUSST |  |  | 6540 | Password given. Not logged for privacy.

01/02/18 08:46:23:162 | [ERROR] |  | AAMEE | Utilities | AUSST |  |  | 6540 | Network failure.                                         

01/02/18 08:46:23:162 | [FATAL] |  | AAMEE | Utilities | AUSST |  |  | 6540 | Could not download Webfeed updaterfeed.xml

01/02/18 08:46:23:162 | [ERROR] |  | AAMEE | Utilities | AUSST |  |  | 6540 | Failed to add Jobs for aam20/win

01/02/18 08:46:32:942 | [FATAL] |  | AAMEE | Utilities | AUSST |  |  | 6540 | Could not download Webfeed updaterfeed.xml

01/02/18 08:46:32:943 | [ERROR] |  | AAMEE | Utilities | AUSST |  |  | 6540 | Failed to add Jobs for aam20/mac

01/02/18 08:46:32:943 | [ERROR] |  | AAMEE | Utilities | AUSST |  |  | 6540 | Failed while preparing jobs

01/02/18 08:46:32:946 | [INFO] |  | AAMEE | Utilities | AUSST |  |  | 6540 | AdobeUpdateServerSetupTool Returned with code: 4.

01/02/18 08:46:32:951 | [INFO] |  | AAMEE | Utilities | AUSST |  |  | 6540 | ************************* END Adobe Update Server Setup *************************

What could be the cause of this error?