3761148 - Unable to Launch Integration Builder (ESR/ID) – "Cannot connect to server using message server: ms://<host>:<port>/P4"

When launching SAP Process Orchestration Integration Builder tools such as:

Enterprise Services Builder (ESR)
Integration Directory (ID)

the login screen appears, but after entering credentials, the following error is displayed:

Cannot connect to server using message server:
ms://xxxxxxxxxxxxxxxxxx.com:8101/P4
Additional traces may show:

Caused by: java.io.IOException:
A HTTP request to the message server returned response code different from "200 OK":
HTTP/1.1 404 Not Found

No P4 access points will be returned

• SAP NetWeaver AS Java 7.5
• SAP Process Orchestration 7.5

Integration Builder, ESR, Enterprise Services Builder, Integration Directory, P4, Java Web Start, cannot connect to server using message server, No P4 access points will be returned, HTTP 404, SAP PO 7.5, Process Orchestration, AS Java, message server, firewall, network restriction, port 50004 , KBA , BC-XI-IBF-LGN , Login/Log off for ESR / IB , Problem