FIX: You cannot send emails to Exchange Online users from Outlook
Automatically fix the undeliverable email issue (delivery has failed to these recipients) when Microsoft Services Sign In is not running or signed in.
What it fixes
- Microsoft Services Sign In Client not running (Microsoft Business Productivity Online Standard Suite)"
- Microsoft Services Sign In Client not signed in (Microsoft Business Productivity Online Standard Suite)"
- Failed delivery to recipients in Outlook nickname cache (NDR 500)
- Microsoft Windows XP
- Windows 7
- Windows Vista
- Windows 8
- Microsoft Office Outlook 2003
- Microsoft Office Outlook 2007
- Microsoft Office Outlook 2007 Service Pack 2
- Microsoft Outlook 2010
- Click the Run now button below
- Then follow the onscreen prompts to launch