I can not send email to anyone using my outlook email account

Question

When ever I am sending an email it goes back with an error

Answer 1

Hello, thank you for reaching out to Microsoft Q&A.

1. May I please know if you are having trouble sending emails to one particular recipient or to all recipients?
2. Do you normally receive all new incoming emails?
3. Is the affected email address for a personal Microsoft account (for example, ending in @outlook.com, @hotmail.com, or a personal @gmail.com that you created for services like Skype or Xbox), or is it a work/school account provided by an organization (for example, ******@company.com)?

Please try the following steps:

1. Open an incognito/private browsing window.
2. Sign in with your account here: https://outlook.live.com/
3. Try sending a test email to another one of your own email accounts.
4. Check whether the message is sent and received successfully.

If the message fails, please share the full bounce-back (non-delivery) error message with us here so we can further investigate.

In addition, please check if you have enough mailbox storage available to send and receive emails in your account.

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Answer 2

Start by checking the exact error text in the “delivery failed” or non‑delivery report (NDR) message. Different errors have different fixes.

For Outlook.com in a browser (Outlook Web):

1. Open the failure message and look for phrases like:
   • “Host unknown” or “Domain lookup failed” → The recipient’s domain doesn’t exist.
     • Check the recipient address for typos (for example, ******@example.con vs someone@example.com).
     • Confirm the recipient’s current email/domain if possible.
   • “Mailbox full” or “Quota exceeded” → The recipient’s mailbox is over its limit.
     • If there is another way to contact the person, ask them to clear space in their mailbox.
   • “Mailbox not found”, “Invalid mailbox”, or “User unknown” → The address is invalid or no longer exists.
     • Verify the address spelling and confirm whether the recipient has a new address.
   • “Mailbox unavailable” → Often a temporary problem on the recipient’s side.
     • Wait a short time and resend.
     • Re‑check the address for typos if it keeps failing.
   • “Message too large” → The email plus attachments exceeds the recipient’s size limit.
     • Remove or compress large attachments.
     • Upload large files to OneDrive and send a sharing link instead.
   • “Connection timed out”, “Can’t connect to remote server”, “No adequate servers”, “Out of memory”, or “Resources temporarily unavailable” → Usually a temporary server or network issue.
     • If the NDR says the recipient’s provider will keep trying, no action is needed.
     • Otherwise, wait a while and resend the message.
   • Errors mentioning “blocked”, “listed in”, or blacklist sites like “spamhaus”, “spamcop”, etc. → The sending server or account is being treated as a spam source.
     • Contact the support team for the recipient’s email provider and request that the account or domain be unblocked.
2. If the error is simply “Your message couldn’t be delivered” with no clear reason:
   • Carefully re‑enter the recipient’s address.
   • Confirm that their email service hasn’t changed domains (for example, from old-domain.com to new-domain.com).

If messages from other providers (like Yahoo) to the Outlook.com address are not arriving at all:

1. Sign in directly to Outlook.com in a browser to rule out client issues.
2. Check:
   • Rules: make sure there are no rules moving or deleting incoming mail.
   • Forwarding: ensure mail is not being forwarded away.
   • Storage: confirm the mailbox is under its storage quota; if it is full, delete or archive mail to free space.

If none of the above matches the error text, copy the exact error wording from the NDR and use it to determine which of the categories above applies, then follow the corresponding fix.

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References:

• Sent email in Outlook.com comes back "delivery failed"
• my outlook email is not delivered - Microsoft Q&A