Sending Error,

Question

Sending Error: 0x800ccc0F,

The connection to the server was interrupted

Answer 1

Hi! Let me help you.

Please follow the steps in the accepted answer in this [link](https://learn.microsoft.com/en-us/answers/questions/5521648/receiving-error-sending-reported-error-(0x800ccc0f).

Answer 2

Error 0x800CCC0F in classic Outlook means the connection to the mail server was interrupted. For Outlook using IMAP/POP, use these steps:

1. Fix the app password (IMAP/POP account)
   1. Sign in to the mail provider’s webmail.
   2. Go to Account Information → Security and create a new app password for Outlook.
   3. Open Outlook.
   4. Select File → under Account Information choose the affected IMAP/POP account.
   5. Select Account Settings → Server Settings.
   6. In IMAP Account Settings, paste the new app password into the Password box.
   7. Select Next, then Done.
   8. Test Send/Receive.
2. If on Windows 10, disable TLS 1.3 (only if error persists)
   1. Close Outlook.
   2. Select Start, search for Regedit, and open Registry Editor.
   3. Browse to: Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols
   4. Under Protocols, check if there is a TLS 1.3 key.
   5. If TLS 1.3 exists:
      • Right‑click Protocols → Export to save a backup of the key.
      • Delete the TLS 1.3 key and all its subkeys.
   6. Close Registry Editor.
   7. Restart Outlook; if still not syncing, restart Windows and test again.

If the issue is with a .pst data file (for example, frequent send/receive problems across accounts), run the Inbox Repair Tool as described in the Outlook data file repair article referenced below.

---

References:

• Outlook IMAP or POP server unexpectedly terminated the connection, and the server was interrupted
• I can't send or receive messages in Outlook