3418231 - Unable to retrieve Access/Refresh token for Oauth Authentication in sender Mail adapter

• While trying to build an interface using Sender mail adapter with OAuth authentication it gets failed with below error while generating Refresh Token.
  Auth Code is retrieved successfully. Attempting to retrieve the Auth Token.
  Status information: Runtime Exception occurred while retrieving Access/Refresh Token. Please collect and check XPI Trace for further information.
  Access/Refresh token cannot be retrieved. Please collect and check XPI Trace for further information.
• At the channel level observed the following error:
  Exception caught during processing mail message; java.io.IOException: Reason: Refresh Token has to be generated again.
  
  From XPI inspector trace with example 100 can see the below exception:
  ssl_debug(12130): Starting handshake (iSaSiLk 5.2) ...
  ssl_debug(12130): Sending v3 client_hello message to <Target URL>, requesting version 3.3...
  ssl_debug(12130): Sending extensions: elliptic_curves (10), renegotiation_info (65281), signature_algorithms (13), server_name (0), ec_point_formats (11)
  ssl_debug(12130): Received v3 server_hello handshake message.
  ssl_debug(12130): Server selected SSL version 3.3.
  ssl_debug(12130): Server created new session AC: 12:00:00:20:C0:96:72...
  ssl_debug(12130): CipherSuite selected by server: TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
  ssl_debug(12130): CompressionMethod selected by server: NULL.
  ssl_debug(12130): TLS extensions sent by the server: renegotiation_info (65281), server_name (0)
  ssl_debug(12130): Server supports secure renegotiation.
  ssl_debug(12130): Received certificate handshake message with server certificate.
  ssl_debug(12130): Server sent a 2048-bit RSA certificate, chain has 2 elements.
  ssl_debug(12130): ChainVerifier: No trusted certificate found, rejected.
  ssl_debug(12130): Sending alert: Alert Fatal: bad certificate. 

  ssl_debug(12130): Shutting down SSL layer...
  ssl_debug(12130): SSLException while handshaking: Peer certificate rejected by ChainVerifier
  ssl_debug(12130): Closing transport.

• SAP NetWeaver 7.50
• SAP Process Orchestration 7.50

Mail Sender, OAuth, Basic Authentication, deprecated, version, configuration, Refresh Token , KBA , BC-XI-CON-MAI , Mail Adapter , BC-JAS-SEC-CPG , Cryptography , Problem