How to fix outlook on iPhone and iMac not sending email?

Hello,

Outlook is actually experiencing service issue right now, so your description of the issue itself can be due to the current ongoing issue.

I quote the relevant content here, but you can also use this link to monitor the issue and get updates: https://status.cloud.microsoft/

User impact: Users may experience intermittent issues signing in to Outlook.com.

More info: Users may experience intermittent sign‑in failures, including “too many requests” errors or unexpected sign‑outs.

Impacted users may include, but are not limited to, iOS users.

iOS users on iPhones must take the following steps to re-enter their password and access their accounts:

-Open the Settings app on your iPhone. -Scroll down and tap on Mail. -Select Accounts under the Mail settings. -Tap on the email account for which you need to reenter the password. -Tap on Account Settings or directly on the Password field (depending on your iOS version). -Enter the updated or correct password in the Password field. -Tap Done to save the changes. -Open the Mail app to confirm that the account is syncing properly and emails are being sent/received.

Current status: The roll back of the previously mentioned configuration change is complete and our telemetry indicates service health is recovering. We'll continue to monitor to confirm this fully resolves the issue.

iOS users must take additional steps to re-enter their password to successfully access Outlook accounts. Please see the steps in the "more info" section above.

Next update by: Monday, April 27, 2026, at 9:00 PM UTC

For Outlook on iPhone and iMac that suddenly stopped sending mail, use these targeted checks and fixes.

1. Verify Outlook service and account status

• Confirm the Microsoft 365 subscription is active and the mailbox is not blocked by storage or security issues.
• If using Outlook.com or Microsoft 365 mail, sign in to the account in a browser and send a test email. If sending fails there, follow the account validation steps under Microsoft account security and verification, then re-test sending.

2. Check for known Outlook send/receive issues

• For Outlook on iMac (classic Outlook for Mac): if messages are stuck in Outbox or not sending, follow the guidance in “I can't send or receive messages in Outlook” for desktop Outlook. This includes:
  • Ensuring the profile is healthy.
  • Verifying account configuration (server names, ports, authentication) and repairing the account if needed.
• For Outlook.com-based accounts, if sending fails due to account validation, use the workaround described under “Cannot send email [WORKAROUND]” and then re-test.

3. Update Outlook and system software

• On iMac (Ventura):
  • Make sure macOS Ventura is fully updated.
  • Make sure Outlook for Mac is updated to the latest build via Microsoft AutoUpdate.
  • Out-of-date Outlook or OS can cause send/receive failures; Microsoft documentation highlights that outdated client software is a common cause of connection and mail flow issues.

4. Repair or reconfigure the mail profile (iMac)

• If the issue started suddenly and persists after updates, recreate or repair the Outlook profile and re-add the email account. Profile corruption is a common cause of send/receive failures.
• If using a POP/IMAP account and seeing errors like 0x800CCC80 on other devices, ensure the account is configured to authenticate correctly to the outgoing (SMTP) server.

5. Use official troubleshooters where applicable

• For Outlook on desktop platforms, Microsoft provides troubleshooters and diagnostics for send/receive issues. From the “Issues sending and receiving email” and “I can't send or receive messages in Outlook” guidance:
  • Run the recommended Outlook troubleshooters for classic Outlook (not applicable to New Outlook for Windows, but the same principles apply to checking configuration and connectivity).

6. Consider Outlook version and integration behavior

• If using New Outlook on Mac or Windows in parallel with iPhone, be aware that some features (like MAPI-based integrations and certain send paths from other Office apps) are only fully supported in Classic Outlook. For reliable sending from desktop, Classic Outlook remains the most compatible option according to current guidance.

7. Purchasing Outlook only

• The provided context does not include licensing or purchase details for Outlook as a standalone product. For purchase options (Outlook-only vs Microsoft 365), use the official Microsoft storefront or contact Microsoft support; licensing specifics are out of scope here.

If, after verifying account status in a browser, updating Outlook and OS, and recreating the Outlook profile on iMac, sending still fails on both iPhone and iMac, the next step is to contact Microsoft support directly and reference that multiple clients (iOS and macOS) cannot send, which points to an account- or service-level issue rather than a single-device configuration problem.

References:

• Issues sending and receiving email
• I can't send or receive messages in Outlook
• Fix Outlook connection problems for Microsoft 365 account
• Fixes or workarounds for recent issues on Outlook.com
• Sending mail from Outlook results in error 0x800ccc80