I receive e-mails with the text "could not be delivered"

Because the AttachingIT plug-in doesn’t do anything with sending the e-mail (but only uploads and encrypts the files), it seems that your settings in Outlook don’t seem right. 

Check your settings here: 

• open Outlook
• Click on 'file' at the top left
• Go to 'account settings' in the menu
• Under the 'email' tab you see the current configured account.

Compare these settings with the information you have received from the Internet provider. This mainly concerns the SMTP server, the port and the type of security. The SMTP server is responsible for sending your e-mails from Outlook. 
 
Are not you completely sure? Then contact your system administrator to have these settings checked.