3505638 - HTTP 407 Proxy Authorization Required

• Outbound HTTP(S) connections from an ABAP system (as the client) that goes via a proxy are failing
• A level 3 ICM trace taken while reproducing the issue discloses similar information as below
  
  Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental.
  
  dev_icm:
  
  [Thr 139744306529856] data (xx) from proxy:
  [Thr 139744306529856] HTTP/1.0 407 Proxy Authorization Required 
  
  (...)
  
  [Thr 139744306529856] *** ERROR => IcmConnInitClientSSL: Proxy connection to <target server> via <proxy host>:<proxy port> failed (proxy returned 407 Proxy Authorization Required) {xx} {root-id=xx} [icxxconn.c 3560]  
  

SAP NetWeaver all versions.

ABAP Platform all versions.

SAP Kernel all versions.

icm, ic, proxy, network, proxy, local, consumer proxy, web services, webservices, web service, webservice, authentication, user, authorization , KBA , BC-CST-IC , Internet Communication Manager , BC-MID-ICF , Internet Communication Framework , BC-ESI-WS-ABA , Web Service and SOAP - ABAP , Problem