Outlook Error 0x800CCC0E: What It Means and How to Fix It (2026 Updated Guide)
Quick answer
Outlook error 0x800CCC0E is a connection error. Outlook is trying to reach an incoming (POP/IMAP) or outgoing (SMTP) mail server and the connection is failing — wrong server settings, blocked ports, broken SMTP authentication, or a corrupted local profile. It’s almost always classic Outlook with an IMAP or POP account. Fix the cause, not the symptom: verify your server settings against your provider’s documentation, confirm SMTP authentication is enabled, and if the settings are correct, rebuild the profile.
Before you start
- Check that other apps can send and receive email through the same account (use the provider’s webmail). If webmail works and Outlook doesn’t, the problem is on the device. If webmail also fails, it’s an account or server problem, not an Outlook one.
- Don’t install third-party “Outlook repair” tools. Most of what you’ll find searching this error is affiliate content selling PST repair utilities. The genuine fixes here are free, built in, and don’t require any download. We do not recommend any of those tools.
- Have your email provider’s server settings to hand before you start. You will need them for at least one of the steps below.
- 0x800CCC0E almost only happens in classic Outlook. The new Outlook for Windows uses a different account model and produces different errors. If you’re in the new Outlook, this guide probably isn’t your error.
What this error means
0x800CCC0E is the error code Outlook returns when it tries to open a TCP connection to a mail server and that connection fails. The most common message is “Cannot connect to the server” or “Your server has unexpectedly terminated the connection.”
The error is connection-layer, not authentication-layer. That distinction matters. An authentication failure (wrong password) gives you a different error. 0x800CCC0E means Outlook tried to reach the server and couldn’t establish or maintain the channel — which can happen for any of several specific reasons, but they all reduce to “the network round-trip didn’t complete.”
Microsoft has noted that 0x800CCC0E sometimes appears alongside 0x800CCC0F or 0x80070057, particularly for users syncing Gmail or Yahoo accounts in classic Outlook. If you see those codes together, treat 0x800CCC0E as the dominant one and work the fix sequence below.
Where this error appears
| Scenario | Likely cause |
|---|---|
| Send/Receive fails on every click; happens immediately | Wrong server name, wrong port, or SMTP authentication off |
| Send/Receive works sometimes; fails intermittently | Antivirus email scanner or firewall interfering; flaky ISP |
| Worked yesterday, failing today, no setting changes | Provider made a server change, antivirus updated and broke port access, or OST file is corrupted |
| Only happens when sending; receiving works | SMTP authentication or outgoing port mismatch |
| Only happens when receiving; sending works | IMAP or POP server name/port mismatch |
| Started after enabling 2-factor authentication on the email account | App password missing — most modern providers require an app-specific password for IMAP/POP/SMTP |
Common causes
The list of causes for 0x800CCC0E is shorter than competitor content suggests. Most “11 reasons” articles inflate the list to fill space. The genuine causes:
- Incorrect server settings. Wrong incoming server name, wrong outgoing server name, wrong port, wrong encryption type. By far the most common.
- SMTP authentication disabled. Many providers require the outgoing server to authenticate with the same credentials as the incoming server. If that checkbox isn’t set in Outlook, sending fails immediately.
- App password required but a regular password is being used. Gmail, Yahoo, Outlook.com, and most major providers in 2026 require an app-specific password when IMAP/POP/SMTP is used with two-factor authentication enabled. The regular account password won’t work.
- Antivirus email scanner intercepting Outlook’s connection. Norton, McAfee, ESET, Bitdefender, and AVG all have email-scan modes that can break Outlook’s SSL handshake. They’re more frequently the cause than the firewall.
- Firewall or corporate network blocking the SMTP port. Some networks block outbound port 25; some ISPs block port 587 to discourage spam. If you can’t reach the port, Outlook reports 0x800CCC0E.
- Corrupted OST or PST file. A damaged local data file can cause repeated send/receive failures. Less common than the others but real.
- Corrupted Outlook profile. A profile that’s accumulated years of cruft can fail to authenticate cleanly even with correct settings. Rebuilding the profile takes 20 minutes and resolves a meaningful share of stubborn cases.
Fixes to try first
1. Verify your server settings against your provider’s published values
This is unglamorous and the cause about half the time. Open File → Account Settings → Account Settings, select your email account, click Change, and check every value.
For most providers in 2026, the correct values are:
| Setting | IMAP (recommended) | POP (legacy) |
|---|---|---|
| Incoming server port | 993 | 995 |
| Incoming encryption | SSL/TLS | SSL/TLS |
| Outgoing server port | 587 | 587 |
| Outgoing encryption | STARTTLS | STARTTLS |
| Outgoing authentication | Required, same as incoming | Required, same as incoming |
Cross-check the server names (e.g., imap.gmail.com, smtp.gmail.com) against the provider’s current documentation. Server names occasionally change.
2. Confirm SMTP authentication is enabled
In Account Settings → Change → More Settings → Outgoing Server, ensure the box “My outgoing server (SMTP) requires authentication” is checked, and “Use same settings as my incoming mail server” is selected. Save and test.
If this was unchecked, you’ve probably found the cause.
3. Generate an app password if you have 2-factor authentication enabled
If your account has 2FA enabled — and most modern accounts do — you need an app-specific password for Outlook to authenticate.
- Gmail: Sign in to your Google Account, go to Security → 2-Step Verification → App passwords, generate a new one for “Mail,” and use that 16-character password in Outlook instead of your regular Google password.
- Outlook.com / Microsoft personal accounts: Sign in at
account.microsoft.com, go to Security → Advanced security options → App passwords. - Yahoo: Account Security → Generate app password.
Replace the password in Outlook with the app password and test. This is the single most common 0x800CCC0E cause we see in 2025–2026.
4. Test with antivirus email scanning temporarily disabled
In your antivirus settings, find the email-scanning or “Mail Shield” feature and disable it. Restart Outlook and try Send/Receive.
If the error stops, the antivirus is the cause. Don’t leave the email scanner permanently disabled — re-enable it and add Outlook (outlook.exe) as an exception, or switch to a different email scanner setting (most antivirus suites have multiple modes; the “scan attachments only” mode rarely breaks Outlook).
5. Test from a different network
Take the device to a different internet connection — phone hotspot is fine. If 0x800CCC0E disappears on the new network, your original network is blocking the SMTP or IMAP port. That’s an ISP or router or workplace-firewall issue, not an Outlook one. Some ISPs block port 25 outbound by default; many corporate networks block port 587 outbound; some require a different port entirely.
If the error persists on a fresh network, the cause is on your device.
Advanced fixes
Repair the OST or PST file
If the data file is corrupted, repeated send/receive failures are common. Microsoft ships scanpst.exe — the Inbox Repair Tool — with every Outlook installation. Find it at:
C:\Program Files (x86)\Microsoft Office\root\Office16\SCANPST.EXE(The path may differ slightly for Microsoft 365 click-to-run installations.)
Close Outlook completely. Run scanpst.exe. Browse to your PST or OST file (typically in C:\Users\<username>\AppData\Local\Microsoft\Outlook\). Run the scan. If errors are found, allow the repair. Then reopen Outlook and test.
For IMAP and Exchange/M365 accounts that use OST files, an alternative to repair is to simply rename the OST file and let Outlook download a fresh copy from the server. Close Outlook, navigate to the OST location, rename <account>.ost to <account>.ost.bak, and reopen Outlook. A new OST will be created automatically. This isn’t lossy because the master copy lives on the server.
Rebuild the Outlook profile
If settings are right, antivirus is ruled out, and the OST is fine, the profile itself may be corrupted.
Open Control Panel → Mail → Show Profiles. Click Add, create a new profile with a different name, and set up your account fresh inside the new profile. Set Outlook to Always use this profile and start Outlook with the new profile.
A clean profile resolves a meaningful share of stubborn 0x800CCC0E cases. Once it’s working, you can delete the old profile.
Run Outlook in safe mode to rule out add-ins
Press Windows + R, type outlook.exe /safe, press Enter. If 0x800CCC0E disappears in safe mode, an add-in is the cause. Open File → Options → Add-ins, disable add-ins one at a time (starting with the most recently installed), and identify the offender.
Reinstall Outlook only as a last resort
A clean reinstall of Microsoft 365 takes around an hour and rarely fixes 0x800CCC0E. If the steps above haven’t worked, reinstalling is a fair next move — but check the related Outlook errors first, in case what you’re actually dealing with is a different problem displaying a similar symptom.
When to stop
Stop and reconsider if:
- The error happens on a brand-new profile, on a different network, with antivirus off, and using verified-correct settings. At that point, the cause is server-side or account-side — not on your device. Contact your email provider.
- You’re being prompted to download a “free PST repair tool” or “Outlook recovery tool” by a search result. That’s affiliate content, not a fix. The genuine repair tool — scanpst.exe — ships with Outlook for free.
- The error shows up alongside Outlook keeps asking for password or Outlook disconnected from server. Those are different problems with overlapping symptoms; work them as separate issues rather than treating 0x800CCC0E as the master cause.
- You’re using a work or school account on a managed device. If your IT admin has device-side restrictions, you may not be able to reach the underlying settings — escalate to the admin rather than fighting the GPO.
Related errors
- Outlook disconnected from server — different symptom, often the same root causes
- Outlook keeps asking for password — the authentication-layer counterpart
Official references
- Microsoft Q&A: How to fix error 0x800CCC0E in Outlook
- Microsoft Support: Repair your Outlook personal folders file (.pst)
- Microsoft Support: Unable to add a Gmail account to classic Outlook