Outlook fix · Windows & Android
Outlook is receiving but not sending emails
If email is coming in fine but nothing goes out, the problem is your outgoing (SMTP) server, not your inbox. Usually it's the SMTP server name or port, a missing authentication tick, or a password that expired. Here's how to check each one, put it right, and get your mail flowing again. Rated 4.9 on Google.
- ● It's an SMTP problem
- ● Port 587 + auth tick
- ● We'll fix it remotely
What's going wrong
Receiving works, sending fails — that's the outgoing server
Your email has two separate connections: incoming (IMAP or POP), which pulls mail into your inbox, and outgoing (SMTP), which pushes mail out. If you're receiving fine, incoming is healthy, so we only need to look at the outgoing side. The usual culprits are:
- Wrong SMTP server name or port. For Microsoft 365 and work accounts it's smtp.office365.com on port 587 with STARTTLS. For a personal Outlook.com or Hotmail account it's smtp-mail.outlook.com on port 587 with STARTTLS. Other providers differ, so check yours.
- Authentication not ticked. The outgoing server needs "My outgoing server (SMTP) requires authentication" switched on, set to use the same login as incoming.
- An expired or changed password. If you recently reset it, the saved outgoing password may be stale.
- Work Offline on, or a big message jammed in the Outbox. Both stop mail leaving even when the settings are perfect.
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The fix
Check and correct your outgoing (SMTP) settings
These steps are for classic Outlook, where you can edit server settings by hand. In the new Outlook or Outlook.com, the account settings are managed for you, so skip to the last step.
- Rule out the easy ones first. On the Send / Receive tab, make sure Work Offline is not highlighted. Then open your Outbox and check nothing large is stuck (if it is, see our stuck-in-Outbox guide).
- Open your account settings. Go to File > Account Settings > Account Settings, click your email account, then Change, then More Settings.
- Turn on outgoing authentication. On the Outgoing Server tab, tick My outgoing server (SMTP) requires authentication and choose Use same settings as my incoming mail server.
- Check the port and encryption. On the Advanced tab, set the outgoing (SMTP) port to 587 with encryption set to STARTTLS (or Auto). If 587 is blocked by your network, some providers accept 465 with SSL/TLS instead.
- Re-enter your password. Click OK, then Next so Outlook tests the settings. If it prompts, type your current password, especially if you've reset it recently.
New Outlook / Outlook.com: you can't hand-edit SMTP here, so first check Microsoft 365 service status for an outage, then remove and re-add the account to refresh its connection. For a Microsoft 365, Outlook.com or other IMAP account, re-adding downloads your mail again from the server, so nothing is lost. If it's a POP account, your only copy of older mail may be stored locally on the PC, not on the server, so back up your Outlook data file (.pst) before removing anything, or ask us to do it safely.
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// GOOD QUESTIONS
Frequently asked
Why is Outlook receiving emails but not sending them?
Because incoming and outgoing use separate connections. If mail arrives fine, your incoming server works, so the fault is on the outgoing (SMTP) side, usually the wrong SMTP server name or port, a missing authentication tick, or an expired password. Correct those and mail flows again.
What are the correct SMTP settings for Outlook?
For Microsoft 365 and work accounts the outgoing server is smtp.office365.com on port 587 with STARTTLS. For a personal Outlook.com or Hotmail account it's smtp-mail.outlook.com on port 587 with STARTTLS. In both cases "My outgoing server requires authentication" must be ticked, using the same login as incoming. Other providers use different server names, so confirm yours with your email host.
Should SMTP be port 587 or 465?
Use port 587 with STARTTLS first, which is the modern standard Microsoft recommends. If your network or ISP blocks 587, some providers accept port 465 with SSL/TLS as an alternative. Only one is needed, so try 587 first and switch to 465 only if it won't connect.
I reset my password and now Outlook won't send. Why?
Outlook may still be using the old outgoing password. In classic Outlook, open File > Account Settings, change the account, and re-enter your new password so the outgoing server can authenticate. If Outlook keeps prompting for the password after that, our password-prompt guide covers the fix.
Nothing sends at all, not just one email. Is that different from a stuck Outbox?
Yes. A single message stuck behind a large attachment is an Outbox jam. If everything refuses to send, it's an outgoing SMTP settings problem, which is what this page fixes. If one big message is the blocker, see our Outlook stuck in Outbox guide instead.
Can you fix Outlook not sending emails remotely?
Yes. Call 365 Techies on 01202 775566 and we'll check and correct your outgoing mail settings remotely over Splashtop SOS, usually within minutes. We phone first, you watch every step, and access ends when we're done. We're Bournemouth-based, same-day, Windows and Android specialists.
Rather not touch the server settings? We'll do it
Outgoing mail settings are fiddly, and one wrong port or tick keeps everything stuck. Call 365 Techies on 01202 775566 and we'll check and correct your SMTP settings remotely over Splashtop SOS, usually within minutes. We phone first, you watch throughout, access ends when we're done. Same-day, Bournemouth-based, 4.9 on Google.
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