Overview
Outlook error 0x800CCC1A ("the server does not support the connection encryption type") means your account’s encryption and port settings do not match what the mail server expects. This guide shows how to correct them and clear the error.
Error 0x800CCC1A is an encryption/port mismatch between Outlook and the mail server.
Key Takeaways
- The error is an encryption type or port mismatch.
- Set the correct SSL/TLS and ports: IMAP 993, POP 995, SMTP 465 or 587.
- Firewalls or antivirus can block secure mail ports.
- A corrupted OST/PST or missing TLS 1.2 can also cause it.
Fix 1 — Set the Correct Encryption and Ports
1. In Outlook, go to File > Account Settings > Account Settings, select your account, and click Change > More Settings > Advanced.
2. Set Incoming server: IMAP 993 (SSL/TLS) or POP 995 (SSL/TLS).
3. Set Outgoing (SMTP) server: 465 (SSL) or 587 (STARTTLS).
4. Choose the correct encryption method for each, click OK, and test the account.
The Outlook error message about connection encryption.
Fix 2 — Check Firewall and Antivirus
1. Temporarily disable third-party antivirus email scanning and the Windows Firewall to test.
2. If Outlook connects, add Outlook and the mail ports as exceptions instead of leaving security off.
3. Re-enable your security software.
Fix 3 — Repair the OST/PST File
1. Close Outlook.
2. Run the Inbox Repair Tool (SCANPST.EXE) from your Office install folder.
3. Point it at your .ost/.pst file and run the scan/repair.
4. Reopen Outlook and test.
Fix 4 — Enable TLS 1.2
1. Open Internet Properties (inetcpl.cpl) > Advanced tab.
2. Ensure "Use TLS 1.2" is ticked (and untick obsolete SSL 3.0/TLS 1.0 if your provider requires it).
3. Apply and restart, then retry Outlook.
Troubleshooting
Problem: Still failing after fixing ports.
Solution: Double-check the exact server names and encryption your provider specifies (many now require an app password too).
Problem: Sending fails but receiving works.
Solution: The SMTP settings are wrong — use port 587 (STARTTLS) or 465 (SSL) with authentication enabled.
Problem: Antivirus keeps blocking it.
Solution: Disable the antivirus’s email/SSL scanning feature, or add Outlook and the mail ports as exclusions.
Problem: The provider needs an app password.
Solution: Generate an app-specific password (for accounts with 2FA) and use it instead of your normal password.
Conclusion
Error 0x800CCC1A comes down to mismatched encryption and ports. Set IMAP 993/POP 995 and SMTP 465/587 with the correct SSL/TLS, clear firewall/antivirus blocks, and ensure TLS 1.2 is enabled — and Outlook will connect securely again.
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