3493734 - '(407) Proxy Authentication Required' error occurs when connect SAC in AO

Error '(407) Proxy Authentication Required' occurs when connecting SAC in AO.
This connection error only occurs in AO, there is no issue connecting SAC directly in browser.

In AO trace, following errors can be found:

|WARN   |AoPlugin | Failed navigating to: https://*.cloud.sap/mobileapp/oauth2/api/v1/token # 
|ERROR  |Con      |  System.Net.WebException: The remote server returned an error: (407) Proxy Authentication Required.
@ System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult, TransportContext& context)
...
 |ERROR  |Con      | Response Info -> Headers: X-Frame-Options: XXX
 ...
Proxy-Authenticate: XXX, ResponseUri: YYY, StatusCode: ProxyAuthenticationRequired #

SAP Analysis for Microsoft Office

1. Open AO.
2. Select 'Insert Data Source' button.
3. Bypass BIP logon screen, select a SAC system, click 'Next' to connect.
4. Connection fails with error:
   'The remote server returned an error: (407) Proxy Authentication Required.'

On user's PC, there is proxy authenticate software being used and it blocks AO to connect to SAC.

To allow AO connect to SAC, please turn off the proxy authentication on user's PC.

To check which URL is blocked and which proxy authentication software is used, please record AO trace as per note 2129389.

In AO trace, the blocked URL can be found in:
|WARN   |AoPlugin | Failed navigating to: https://*.cloud.sap/mobileapp/oauth2/api/v1/token # 

And the name of the used proxy authenticate software can be found in field 'Proxy-Authenticate'. For example, McAfee Web Gateway, NTLM etc.
|ERROR  |Con      | Response Info -> Headers: X-Frame-Options: XXX
 ...
Proxy-Authenticate: McAfee Web Gateway, ResponseUri: YYY, StatusCode: ProxyAuthenticationRequired #

Analysis Office, Analysis for Office, A4O, Analysis for Excel, A4O, SAP Analytic Cloud, SAC tenant , KBA , BI-RA-AO-XLA , Excel Addin , Problem