3286340 - Error "Message is incomplete" while trying to download or upload SAP note using SNOTE

While trying to implement or manually upload any SAP note using SNOTE tool, below error is seen:

"Message is incomplete (severity, area, number or exception is missing).
Message no. BL203"

Case 1: In dev_w* log:
"User XXXX is not authorized to start TP"

RFC 1764  CONVID 89023329
 * CMRC=6 DATA=0 STATUS=0 SAPRC=676 ThSAPOCMINIT
RFC> ABAP Programm: SAPLCRFC (Transaction: SNOTE)
RFC> User: XXXX (Client: XXX)
RFC> Destination: %_TCPIP_%1 (handle: 3, DtConId: 63AD1B012EBE0EA0E10080000A4221CB, DtConCnt: 0, ConvId: ,)

Also, perform TCP/IP connection test in sm59 and the connection test failed will fail with Return code 676

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

                                                                                     OR 

Case 2: Below error message is seen in work logs while downloading SAP Note via SNOTE:

SAPXPG_START_XPG_LONG: sy-subrc: 1006 number of retries =  1
"RFC error message: command Y:\usr\sap\<SID>\XXX\exe\SAPCAR not allowed"

• SAP Note Assistant (SNOTE)
• SAP Netweaver ABAP

SNOTE, NOTE, Download, Upload, Message is incomplete, (severity, area, number or exception is missing), BL203, User, not authorized to start TP, rfcecec on host, Return code 676, TCP/IP, SAPXPG_START_XPG_LONG, sy-subrc: 1006, RFC error message, command, SAPCAR not allowed , KBA , BC-UPG-NA , Note Assistant , Problem