2873837 - Fiori My Travel and Expense fails to attach an attachment: PAOC_TRV_SRV Services fails to attach a picture or attachment files (PDF, DOC and others)

• Trying to attach a .jpg file or any file (.PDF, .DOC and others) to an expense type (Product: Fiori My Travel and Expense) and after posting this attachment, we are getting 401 Unauthorized error in the Front-end gateway
• When we check the back-end content server system, the user error failed to check logon failed
  
  ~~~~~~~~~~Error Seen~~~~~~~~~~~~~~~
  POST https://domain:8001/sap/opu/odata/sap/PAOC_TRV_SRV/Expenses('0000XXXXXXXXX_____E00X_____')/Attachments 400 (Bad Request)  - Where XXXXXXXXX is the Expense ID tied to this attachment
  ~~~~~~~~~~~End~~~~~~~~~~~~~~~~~~
• While attaching the failed attachment, SAP SLG1 still shows a transaction occuring:
  
  ~~~~~~~Example SLG1~~~~~~~~~~~~~~~
  Object________________ SCMS (KPRO: Content Management Service)
  Subobject_____________ HTTP (HTTP communication)
  External ID___________
  Log number____________ 000000000000XXXXX (Where XXXXX is the log number for SLG1)
  ..
  ..
  Transaction code______
  Program_______________ SAPLSCMS_HTTP
  Operating mode________ D (Dialog processing)
  ..
  ..
  Object________________ /IWBEP/ (SAP NetWeaver Gateway Backend Enablement & Event Publishing)
  Subobject_____________ RUNTIM (Runtime Processes)
  External ID___________ XXXXXXX (Where XXXXXX is the External ID)
  Log number____________ 000000000000XXXXX (Where XXXXX is the Log number)
  
  ~~~~~~~~~~end~~~~~~~~~~~~~~~~~~~~
  
  
• References: My Travel and Expense: Read the main manual of My Travel And Expense document attachment link above or main manual: https://help.sap.com/viewer/f4153779fcb742c094bb6157c0ff1cbe/1809.002/en-US/86b93fd235ef4499a28cfa433083af7f.html?q=attachment
• Fiori My Travel and Expense works except when attaching a file to it and it fails with the errors above

My Travel and Expense (SAP Fiori Finance) Fiori app (F0584 or F0584A)

"Fail to save attachment to My Travel and Expense Fiori app","File attachment issue Fiori","Content Server issue with Fiori","PAOC_TRV_SRV  attachment issue","Error attaching a file to Fiori","KPRO: Content Management Service and Fiori","Fiori 400 (Bad Request)" , KBA , FI-FIO-TV-MTE , My Travel and Expenses , BC-SRV-KPR-CS , SAP Content Server , Problem