Outlook problems · Classic Outlook
How to fix Outlook error 0x800CCC1A
Error 0x800CCC1A means Outlook couldn't make a secure (SSL/TLS) connection to your mail server — nearly always a wrong port or encryption setting. Set the correct secure ports (IMAP 993, POP 995, SMTP 587 or 465), test with your antivirus email scanning off, and for Gmail or Microsoft accounts re-add the account so it uses modern OAuth2 sign-in. Here's how — or we'll fix it remotely in minutes. Rated 4.9 on Google.
- ● Classic Outlook
- ● Windows only
- ● Secure port fix
Plain English
What error 0x800CCC1A means
0x800CCC1A is a send/receive error that means Outlook tried to open a secure (SSL/TLS) connection to your incoming or outgoing mail server and the handshake failed. The two servers couldn't agree on how to encrypt the conversation — usually because the port number or the encryption type in your account settings doesn't match what the server expects.
You'll see it worded a couple of ways: "your server does not support the connection encryption type you have specified", or a plain "sending/receiving reported error (0x800CCC1A)". Either way the cause is the same family of settings, and once the ports are right the error disappears for good.
Two other things can trigger it: antivirus or firewall software intercepting the encrypted handshake, and — increasingly common in 2026 — providers like Gmail and Microsoft retiring old basic-auth sign-in and requiring modern authentication (OAuth2), which the old port-only setup can't do. We cover all three below. This is for classic Outlook on Windows (2016, 2019, 2021, Microsoft 365 desktop).
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The main fix
Set the correct secure ports and encryption
This is the fix that resolves 0x800CCC1A most of the time on ISP and third-party mailboxes (BT, Sky, TalkTalk and business hosts). In classic Outlook, go to File > Account Settings > Account Settings, double-click your email account, then click More Settings > Advanced. Match your setup to these — the key is that the port and the encryption drop-down agree with each other:
- IMAP incoming: port 993, encryption SSL/TLS.
- POP incoming: port 995, encryption SSL/TLS.
- SMTP outgoing: port 587 with encryption STARTTLS (the modern default) — or, if your provider still prefers it, port 465 with SSL/TLS.
While you're on the Outgoing Server tab, make sure My outgoing server (SMTP) requires authentication is ticked and set to Use same settings as my incoming mail server — most SMTP failures are actually a missing tick here. Click OK, then Next to let Outlook test the settings, and press F9.
Not sure of your provider's exact values? BT, Sky, TalkTalk and business hosts each publish them — get the wrong port and 0x800CCC1A returns, so it's worth confirming. One caveat: if the account is a Gmail, Outlook.com or Microsoft 365 mailbox, changing ports alone won't fix it — those providers now require OAuth2, so jump to the next section. We know the common UK ISP values and can set them for you.
If ports are correct
Test with antivirus off, then re-add for OAuth2
If your ports are definitely right and the error persists, two things are usually behind it.
1. Antivirus or firewall is intercepting the handshake. Many security suites (Avast, AVG, Norton, ESET and others) have an email scanning feature that sits between Outlook and the server and can break the SSL negotiation. Temporarily turn off email/mail scanning in your antivirus — and, if needed, test with Windows Firewall briefly off — then send/receive. If that clears it, don't leave protection off: instead add Outlook (and the secure ports 993/995/465) as an exception, or simply leave the AV's email scanning disabled, as modern SSL already secures the mail.
2. Your provider now requires modern authentication (OAuth2). Google disabled basic-auth sign-in for Gmail in March 2025, and Microsoft is retiring it for Outlook.com and Microsoft 365 through 2026 — so a mailbox set up the old port-only way simply can no longer authenticate, no matter what ports you use. The cleanest fix is to remove and re-add the account: File > Account Settings > Account Settings, select the account, click Remove, then New and add it again. When you re-add it, Outlook opens the provider's own web sign-in window — that's OAuth2 — and configures the secure ports automatically. For Gmail, if you're using an older client that can't do OAuth2 you can instead generate an app password (this requires 2-Step Verification to be switched on) and paste that in place of your normal password.
Removing and re-adding an IMAP or Microsoft 365 account is safe — the mail re-downloads from the server. If it's a POP3 account, your messages live only in the local PST, so back that PST up before you remove anything.
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Frequently asked
What does Outlook error 0x800CCC1A mean?
It means Outlook couldn't establish a secure SSL/TLS connection to your mail server. Almost always the port number or the encryption type in your account settings doesn't match what the server expects — for example POP on 995 needs SSL/TLS, not None. Fixing the ports normally clears it, though Gmail and Microsoft accounts also need modern OAuth2 sign-in.
What are the correct secure port settings for Outlook?
For a secure connection: IMAP incoming 993 with SSL/TLS, POP incoming 995 with SSL/TLS, and SMTP outgoing 587 with STARTTLS (or 465 with SSL/TLS if your provider prefers). The port and the encryption drop-down must agree, and your outgoing server should be set to require authentication.
Can antivirus cause error 0x800CCC1A?
Yes. Email-scanning features in security suites like Avast, AVG, Norton or ESET sit between Outlook and the server and can break the encrypted handshake. Temporarily disable email scanning to test. If that fixes it, add Outlook and the secure ports as an exception, or leave email scanning off — modern SSL already protects the mail in transit.
Why does re-adding my Gmail or Microsoft account fix 0x800CCC1A?
Because Google (Gmail, from March 2025) and Microsoft (Outlook.com and Microsoft 365, through 2026) have retired old basic-auth sign-in and now require modern authentication (OAuth2). An account set up the old port-only way can no longer authenticate, so changing ports won't help. Removing and re-adding it makes Outlook use the provider's secure web sign-in and set the correct ports automatically.
Is it safe to remove and re-add my email account?
For IMAP or Microsoft 365 accounts, yes — your mail lives on the server and re-downloads when you add the account back. For a POP3 account, your messages are stored only in the local PST file, so back that PST up before removing the account so nothing is lost.
Can 365 Techies fix error 0x800CCC1A for me?
Yes. Call 01202 775566 and we'll connect remotely with Splashtop — we phone first, you watch every step, and access ends when we're done. We'll set the correct secure ports, test the connection, sort any antivirus conflict, and re-add the account for OAuth2 if needed, usually in minutes.
Ports not sticking?
Call 01202 775566 and we'll set the secure ports and encryption for you, test the connection, and re-add the account for OAuth2 if needed — all remotely while you watch. Usually done in minutes.
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