2519204 - ReX users cannot register/ synchronize with SMP with error codes: -1305, 86, 404, 500

ReX users cannot register/ synchronize with SMP through Relay Server to ERP/ CRM system.

ReX logs show the below error messages:

[ERROR  ]:onHttpCommunicationError: Http Communication Failure, Erro Code =86, = MobiLink synchronization communication error: 404,
[ERROR  ]:On Registration success: exception name :SUPSynchronizeException, reason: Sync failed: -1305 (MOBILINK_COMMUNICATIONS_ERROR) %1:86 %2:404 %3:0;Parameter 1:86;Parameter 2:404;Parameter 3:0
[ERROR  ]:Exception description: SUPSynchronizeException: Sync failed: -1305 (MOBILINK_COMMUNICATIONS_ERROR) %1:86 %2:404 %3:0;Parameter 1:86;Parameter 2:404;Parameter 3:0

SMP log shows:

HttpdSync ERROR SetRequestComplete request dropped due to invalid request handle
...
ERROR=SUPPersistenceException from synchronize: -- SUPSynchronizeException: Sync failed: -1305 (MOBILINK_COMMUNICATIONS_ERROR) %1:86 %2:500 %3:0;Parameter 1:86;Parameter 2:500;Parameter 3:0

• SAP Retail Execution (ReX) 3.4.5
• SAP Mobile Platform (SMP) 3.0 SP13 MBO Runtime
• SAP Relay Server 16.5 or 17
• SAP CRM/ SAP ERP

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