Outlook IMAP/SMTP Synchronization Fails with error 800CCC0E-0-0-733

Question

Outlook IMAP/SMTP Synchronization Fails with error 800CCC0E-0-0-733

Robert Ludwig 25

Recently, Outlook synchronization started to fail for my Gmail account with the above error. I tried repairing the account to no avail. I recently deleted the account from Outlook (and the system). I had to re-add the account using the Control Panel Email settings and finally achieved a connection when I turned on 2-factor authentication in Google and added separate app passwords for IMAP and SMTP. However, Outlook still fails to synchronize the folders reporting the above error in IMAP.

Gabe Bratton 636 Reputation points Microsoft Employee Moderator

2026-03-11T20:10:28.0933333+00:00

Just for awareness there is a bug affecting Gmail and Yahoo that we have escalated. We posted a Known Issue to share status and a workaround, https://support.microsoft.com/en-us/office/users-get-errors-0x800ccc0e-0x800ccc0f-synchronizing-gmail-and-yahoo-accounts-in-classic-outlook-e5a7b684-7c5c-4848-ab2d-d48291451f67.

Answer accepted by question author

0 additional answers

Your answer

Gabe Bratton 636 Reputation points Microsoft Employee Moderator

2026-03-11T20:10:28.0933333+00:00

Just for awareness there is a bug affecting Gmail and Yahoo that we have escalated. We posted a Known Issue to share status and a workaround, https://support.microsoft.com/en-us/office/users-get-errors-0x800ccc0e-0x800ccc0f-synchronizing-gmail-and-yahoo-accounts-in-classic-outlook-e5a7b684-7c5c-4848-ab2d-d48291451f67.

Answer 1

Hi Robert Ludwig,

Thank you for reaching out to Microsoft Q&A forum.

Based on your description, the situation where Outlook can connect to Gmail but fails to synchronize IMAP folders with code 800CCC0E‑0‑0‑733 is commonly related to Google authorization (consent) or cached OAuth credentials for Gmail in Classic Outlook.

You can try the following steps in order:

Update Outlook and use “Retry”

Open Outlook > File > Office Account > Update Options > Update Now to make sure Outlook is fully up to date.
Run Send/Receive to trigger the error message, then select Retry (if Outlook shows this option).
When the Google sign‑in page opens, make sure to check the permission box for Microsoft apps & services:
- “Read, compose, send, and permanently delete all your email from Gmail”, then complete the sign‑in process.

If you do not see “Retry” (or you already tried it but folders still do not sync): use the manual Microsoft workaround

Remove Microsoft apps & services access in Google

Close Outlook.
Sign in to your Google account > Manage your Google Account > Security > Your connections to third‑party apps & services > Microsoft apps & services > Remove all access > Confirm.

Delete Google IMAP OAuth2 credentials in Windows

Open Credential Manager > Windows Credentials > Generic Credentials.
Look for entries starting with MicrosoftOffice16_Data:OAUTH2 and, when expanded or hovered, containing tp_google_imap_Oauth2.
Select Remove for those entries (there are usually two entries per Gmail account).

Sign in again from Outlook

Reopen Outlook and add/sign in to the Gmail account again so that Outlook launches the browser-based sign‑in.
Make sure the correct Gmail email permission is selected, as described in step 1.

Additional note:

If you added the account via Control Panel > Mail and synchronization remains unstable, try removing the account and adding it again from inside Outlook (File > Account Settings > New).

Quick check on the Gmail side (to avoid missing IMAP requirements)

Go to Gmail Settings > Forwarding and POP/IMAP and confirm that Enable IMAP is turned on.
Enabling 2‑Step Verification and using an App Password is the correct approach and is commonly required when connecting Gmail via IMAP.

If folders still do not synchronize

The next recommended step is to create a new Outlook profile and then add the Gmail account again to clear any local profile configuration.

Please feel free to let me know if you have any further updates, thanks.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread

Robert Ludwig 25 Reputation points

2026-03-11T19:44:00.3833333+00:00

Thank you!!!

After three days of thrashing with Google sign-on credentials, the OAUTH2 credentials turned out to be the problem. I couldn't identify which one was specific to the ID I was having problems with, so I removed them all and then repaired each of the Gmail IDs to get them all working again.

You're a life saver.

The AI answer that I rejected because I had already tried all those things did not cover the OAUTH2 credentials.
Chloe-V 6,000 Reputation points Microsoft External Staff Moderator

2026-03-12T08:33:21.2566667+00:00

Hi Robert Ludwig,

Glad to hear it’s working now!

Thanks for sharing what fixed it — re‑creating the OAuth2 credentials definitely did the trick.

If anything else comes up, feel free to post back anytime.
Robert Ludwig 25 Reputation points

2026-03-12T17:22:44.86+00:00

Chloe-V,

Your fix for the OAUTH2 data corrected the problem at first, however, it has started happening again with one of the Gmail accounts. Was there some change to Windows that affected the handling of the OAUTH2 credentials recently that might be causing them to cease functioning properly?

Looking at the OAUTH2 credentials for Gmail, the User Name is missing from the records so I can't tell which credential applies to which email address. This seems to be true in all the Gmail credentials including the ones that still work.

EDIT: Some of the OAUTH2 credentials have the User Name, some do not. EDIT2: Repair does not fix the problem.
Chloe-V 6,000 Reputation points Microsoft External Staff Moderator

2026-03-13T00:19:58.2766667+00:00

Hi Robert Ludwig,

Thank you for the update — I’m glad to hear that clearing the OAuth2 credentials helped initially, and I understand how frustrating it is when the behavior returns.

Microsoft has acknowledged reports of synchronization behavior (0x800CCC0E / 0x800CCC0F) with Gmail and Yahoo accounts in classic Outlook and is continuing to review this. You can follow the latest information here:

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

Regarding Credential Manager: this can occur because OAuth entries stored there do not always display clear or easily recognizable identifiers. If you’re unable to determine which entry corresponds to which email address, the simplest approach is to remove all entries containing tp_google_imap_Oauth2, then sign back into each Gmail account again.

If the behavior continues after completing the steps above, the next isolation step would be to create a new Outlook profile and add the Gmail account there, to rule out any corruption in the current local Outlook profile.

Share via

Outlook IMAP/SMTP Synchronization Fails with error 800CCC0E-0-0-733

0 additional answers

Your answer