EMAIL ISSUES WITH OUTLOOK

Use the following checks in order.

1. Confirm internet access

• Open a browser (for example, Microsoft Edge or Google Chrome).
• Browse to http://www.microsoft.com or http://www.bing.com.
• If these sites do not load, fix the network first using the steps in Fix network connection issues in Windows.

2. Check Outlook.com sending limits and non‑delivery reports

• If messages bounce back with a non‑delivery receipt (NDR), read the error text. Common causes include:
  • Invalid recipient address
  • Recipient mailbox full
  • Recipient server issues
  • Message blocked as spam
• If the address is correct but NDRs continue, use the guidance in Sender Support in Outlook.com.
• If the Outlook.com account is new, a low sending quota may temporarily block sending until enough normal usage is established. See Sending limits in Outlook.com.

3. Check attachment size

• If an email has attachments larger than 25 MB, Outlook.com will not send it.
• Remove or reduce large attachments, or share them via a link, then resend.

4. Check for issues specific to Outlook.com

• If sending fails only from Outlook.com but not from other accounts, verify:
  • The recipient has not blocked the address.
  • The recipient adds the address to their safe senders list if messages are being filtered.
  • The recipient is in Contacts on Outlook.com.

5. If using Outlook for Windows with the Outlook.com account

• Make sure Outlook is not showing “Disconnected”, “Working Offline”, or “Trying to connect…” in the status bar. If it is:
  • Go to the Send/Receive tab and select Work Offline to toggle back online.
• Confirm the PC is online as in step 1.
• Check for large messages stuck in the Outbox (especially >20 MB). If found, open the oldest stuck message, remove or reduce attachments, then send again.
• If the password for the Outlook.com account was recently changed on the web, update it in Outlook for Windows as well.
• If Outlook still cannot send/receive, repair the Outlook profile and, if needed, repair the Office installation.

If these steps do not restore sending and receiving, follow the more detailed flow in the Outlook “I can’t send or receive messages” article for either Outlook.com or Outlook for Windows, depending on where the problem occurs.

References:

• Can't send or receive email in Outlook.com
• I can't send or receive messages in Outlook