3185340 - SAP PI/PO Error: "SSLException while handshaking:handshake failure" when connecting to SAP Ariba Cloud Integration Gateway (CIG)

After CIG TLS 1.2 cipher suites hardening activity all my SAP Process Integration/Process Orchestration (PI/PO) outbound messages sent to Ariba Cloud Integration Gateway (CIG) are failing with below SSL handshake error in XPI inspector > SSL Example 11 traces:

Error: Begin IAIK Debug:
ssl_debug(xx): Starting handshake (iSaSiLk xxx)...
ssl_debug(xx): Sending v3 client_hello message to acig.ariba.com:443, requesting version x.x...
ssl_debug(xx): Sending extensions: renegotiation_info (xxxx), signature_algorithms (xx)
ssl_debug(xx): Received alert message: Alert Fatal: handshake failure
ssl_debug(xx): SSLException while handshaking: Peer sent alert: Alert Fatal: handshake failure
ssl_debug(xx): Shutting down SSL layer...
ssl_debug(xx): Closing transport...

End IAIK Debug.

Read more...

Ariba Network all versions ; Ariba Procurement, cloud edition all versions ; Ariba Sourcing, cloud edition all versions ; SAP Ariba Procurement, cloud edition all versions ; SAP Ariba Sourcing, cloud edition all versions ; SAP Business Network for Procurement all versions

TLS 1.2 cipher suite hardening; TLS 1.2 ciphers CIG;  ECDHE; TLS1.2; DHE; acig.ariba.com; testacig.ariba.com , KBA , BNS-ARI-CI-AN , Managed Gateway for Business Network , BNS-ARI-CI-SCC-BUY , CIG Add-on for Buyer SAP Business Network SCC Integration , BNS-ARI-CI-SRC , Managed Gateway for Sourcing Integration , Problem