Mail-enabled public folders not receiving external mail.

Greetings,

I need some help with a situation that has been ongoing for the past couple of days - All our mail enabled public folders have stopped receiving external mail. Internal works fine.

Our environment is setup as below:

- Exchange 2013 CU7 - Version: Version 15.0 (Build 1044.25)

Public Folder created > "Showroom" > under one subfolder from the root

• Mail      Enabled: YES
• SMTP      Address configured: YES
• Mail      Flow Settings    
  • Accept       Messages from: All senders
  • Require       that all senders are authenticated: False
  • Reject       messages from: {}
• ExternalEmailAddress:     
• RequireSenderAuthenticationEnabled:      False
• Folder      Permissions:    
  • Myself:       Owner
  • Default:       Author
  • Anonymous:       Contributor

Carlos