The dreaded 0x800CCC0F sending error

I followed this with my own test email to the same account, with only "test" in the subject line, and the body. It was successful. I then attempted to send an email with three attachments (a Word doc and two spreads, all fairly small), and I got the dreaded 0x800CCC0F sending error. This, following a login into gmail, and a clearing of the trash folder.

Well, we know 2 things from your description, -the account is correctly configured and is working for send/receive

That leaves only one thing - something is interfering with Outlook

Most common cause for this kind of scenario is an anti-virus taking longer to do its thing then what Outlook has as per its server timeout setting for the account

Quick test

#1 - If you send a test message with only 1 attachment - does it work? If no, if you try with one of the other attachments - same result? (i.e. if the first was a Word doc - use an Excel file)

#2 - If it works with one, does it work 2 etc?

If Endpoint is installed on Win11, and things aren't working, would suggest uninstalling Endpoint completely for the time being, reboot the machine. repairing Office and trying the tests again

Hi Karl, to quickly reply before heading to bed (after midnight ET) - I'll experiment in the a.m. with fewer attachments. But just to point out, this is an out-of-the-box Lenovo Windows 10 computer, followed by the free Windows 11 upgrade. I haven't installed Symantec Endpoint, or tinkered with Defender in any way.

Hi Karl, to quickly reply before heading to bed (after midnight ET) - I'll experiment in the a.m. with fewer attachments. But just to point out, this is an out-of-the-box Lenovo Windows 10 computer, followed by the free Windows 11 upgrade. I haven't installed Symantec Endpoint, or tinkered with Defender in any way.

Then the only thing left to play with is the server timeout setting - really don't know what else to suggest given that this is a vanilla system other then trying to connect to Google support to see if they have any words of wisdom to share.

Well, nothing is going outbound at the moment (I continue to receive emails into the account); no sense in trying more or less attachments. I did extend the connection time to three minutes, but before that time is up, I get the 'The connection to the server was interrupted. If this problem continues, contact your server administrator or Internet service provider (ISP)' message. However, last time I was on the horn with Google, they suggested I should contact Microsoft, deeming it a problem with Outlook.

And so it goes. It seems to me: There ought to be some diagnostic tool, that see what is or isn't going out of Outlook, and what is or isn't coming back from Google; and if something does come back, what it is unhappy about besides "the connection was interrupted".

I am at a total loss here. I've been able to manage 20+ years of email, archived to .pst, with Outlook; and now the whole system I've set up is broken. Even after buying a new computer, and moving my Office license to it. And I just don't know why, nor does it appear I will ever know.

Given everything to date, unfortunately I don't have any additional suggestions.

Given that has involved two different systems where one is a new relatively virgin install - the only common element in this is the Google account. It certainly is not a generic problem since the forum here would be lit up like a XMas tree given the large number of Google email account users.

Normally I would suggest checking in with Microsoft Support but mainstream support for '2016 ended Oct '2020.

One last thing that you can try in the unlikely chance it would make any difference is to try this using Outlook '365 (via the free 30 day trial version)

Free Trial - Try Microsoft 365 for a month - Microsoft Store

If you do decide to try this -

#1 - Make sure to turn of recurring billing so that it doesn't automatically charge your credit card at the end of the trial period

Turn recurring billing on or off for Microsoft 365 for home https://support.microsoft.com/en-us/office/turn-recurring-billing-on-or-off-for-microsoft-365-for-home-c7c0bc32-9744-4acf-9818-815d5c96cc59

#2 - Before installing '365 - uninstall '2016

*** if things work, you can verify that this is strictly a '2016 issue by uninstall '365 and re-installing '2016 to see if still has the same problems