2599578 - Create Attachment with .csv extension, SO424 Error occurred during import / 1R557 Content-Type msexcel2 is not permitted

When the user creates attachment with .csv extension in transaction SBWP, SO00 or SO01 -> New message,
the following error appears:

• Message number
  SO424 Error occurred during import
  
  
• Message number in SLG1:
  1R557 Content-Type msexcel2 is not permitted
  
  
  „Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental."

• SAP Basis Release 700 or higher
• SAPOffice

SO00, SO01, SO424, 1R557, msexcel2, Error, during, import, Content-Type, permitted, csv, sbwp, , KBA , BC-SRV-COM , Communication Services: Mail, Fax, SMS, Telephony , BC-CI-WEBR , WebRFC, WebReporting , Problem