Users get errors 0x800CCC0E & 0x800CCC0F synchronizing Gmail and Yahoo accounts in classic Outlook

Last Updated: March 16, 2026

ISSUE

Some Gmail and Yahoo accounts stopped syncing as of February 26, 2026. Accounts could also stop syncing after a password change. In both cases when Outlook stops syncing you are no longer prompted to sign in to your account.

You get errors like the following: Task 'Synchronizing subscribed folders for username@gmail.com.' reported error (0x800CCC0E) : 'Outlook cannot synchronize subscribed folders for username@gmail.com.

Sending reported error (0x800CCC0F) or Sending reported error (0x80070057)

Check for new mail reported error (0x800CCC0E)

Outlook send receive progress

STATUS: INVESTIGATING

The Outlook Team is investigating this issue. We will update this topic with fix status as soon as we get it.

WORKAROUND

When Outlook is not syncing, it is happening in part because Outlook is not prompting you to sign in and refresh the credentials. The workaround steps below are expected to cause Outlook to prompt you to sign in to your account. These steps do not remove or otherwise affect the account.

Close Outlook.
From the Windows Start menu, search for Credential Manager and open it. On Windows 10 you may need to open the Control Panel to access Credential Manager. For more information, please go to Accessing Credential Manager.
Under Manage your credentials, select Windows Credentials.
Scroll down to Generic credentials and locate those starting with MicrosoftOffice16_Data:OAUTH2.
Expand each of these and hover over MicrosoftOffice16_Data:OAUTH2 until it shows the full name including the tp_google_imap_Oauth2 or tp_yahoo_imap_Oauth2. These are the credentials for your account.
Select Remove for each of these with the MicrosoftOffice16_Data:OAUTH2. There are two or four of these credentials for each Gmail & Yahoo account so make sure you remove each of them.
1. If you want to avoid removing Google or Yahoo IMAP credentials except for the specific affected account, you can map the credentials by comparing them to the identities in this registry key below. Open Registry Editor and paste this path in the Address bar at the top. Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity\Identities
2. The sub keys to this registry key above include your Gmail or Yahoo identity. At the beginning of the identity registry key is a number that matches your Gmail or Yahoo credential in Credential Manager. See the examples below for reference.
3. In the case above the registry key starts with 11526349….
Restart Outlook and sign in to your Gmail or Yahoo account.
Restart Outlook again after you sign in if it does not start syncing right away.

If the first set of steps above do not address the issue, use the steps below to remove the identity registry key for the account. These steps are expected to cause Outlook to prompt you to sign in to your account. These steps do not remove or otherwise affect the account.

Close Outlook.
Right click the Windows Start Button, select Run, type Regedit and select OK.
Paste the path below in the Regedit Address Bar and press Enter.Computer\HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity\Identities
Under the Identities key, select each sub key until you find the one that matches the email address that is not syncing.
Delete the Identities registry key, example in red below. Look for the corresponding Gmail or Yahoo email address, example in purple. That is the identity key in the left column to delete. After you delete the key, restart Outlook and sign in again.