3657377 - Error "cannot create substitution rule due to internal error" when adding substitutes Fiori My Inbox

When creating a substitution rule in the "Manage my substitutes" section of the Fiori app "My Inbox", the errors like the following raised.

"Cannot create substitution rule due to an internal error. Please try again later. Contact your system administrator if the problem persists.
RFC call was not successful because of communication failure 'Message E ZWF 000 cannot be processed in plugin mode HTTPS'"

Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental.

• Task Gateway
• Gateway Business Workflow Enablement
• SAP Business Workflow 
• SAP NetWeaver
• SAP Web Application Server for SAP S/4 HANA
• ABAP PLATFORM - Application Server ABAP
• SAP Gateway

SAP_GWFND, IW_PGW, /IWPGW/TGW, /IWWRK/WORKFLOW, IW_BEP, TASKPROCESSING, SWF_WORKFLOW, fiori my inbox, manage my substitute, substitution rule error, plugin mode HTTPS, RFC call failure, task gateway, BADI WF_SUBSTITUTE, internal error, E 00 001, SAP S/4HANA, substitution period, error message, custom implementation, BADI deactivation, Message E 00 001 cannot be processed in plugin mode HTTPS , KBA , OPU-BSC-TGW , Task Gateway , BC-BMT-WFM , Business Workflow , Problem