Outlook 365 - suddenly unable to send using Gmail POP3

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Senior Member
Outlook version
Outlook 2016 32 bit
Email Account
Office 365 Exchange
Suddenly communicating with Gmail servers stopped working. I didn't change anything, but got an error "Sending' reported error (0x800CCC1A) : 'Your server does not support the connection encryption type you have specified. Try changing the encryption method. Contact your mail server administrator or Internet service provider (ISP) for additional assistance.'
I removed the Gmail accounts and tried to re-install them, but no luck.
They are POP3 accounts and the settings were fine, until very recently. Yesterday(?)

Am using the latest Outlook 365 version (1910 build 12130.20272 Click-to-Run).
Didn't change anything within my Google account.

I know IMAP is the way to go, but as long as POP3 is available... I have many archive .pst files.

Any suggestions?
Is this a Gmail issue or my ISP ?

Both, incoming and outgoing. Created a new mail account (3rd time): Outlook > File > Account Settings > Manage Profiles > Mail Setup.
Bad luck.
Allow less secure apps is set to 'ON'.

Outlook-POP3-Gmail-Cannot communicate with server-issue-15112019 064345.png

BTW ... It strikes me, when adding an account using File>Account Settings>Add Account, the option:
"My outgoing server (SMTP) requires authentication" is missing, contrary to mail setup in the above way (using 'manage profiles').

Outlook-POP3-Gmail-My outgoing server requires authentication-missing-15112019 070154.png

Peculiar it is...

There is an article about this issue and the suggestion was made to uncheck the option "This server requires an encrypted connection(SSL)"
Tried that, didn't work either.
Last edited:
I've seen a few reports in Microsoft forums too. It's working here - with imap and 2FA. I'll test it on a second account that does not have 2FA enabled.

I know from experience with gmail, is they will turn off 2FA and make you review recent access before they will let you connect.
It worked here with manual setup, POP account, and no 2FA. Autoaccount setup was failing - then i remembered i wanted to do a POP account, since you are doing pop.
Hi Diane, meanwhile found the solution:
change a registry key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\SecurityProviders\SCHANNEL\Protocols\TLS 1.3\Client
set Enabled to 0
(it is set to 1 by default)
TenForums: Outlook cannot connect to GMail - Windows 10 Help Forums
Gmail Help Forum: Outlook 365 - Gmail-POP3 - (0x800CCC1A) : 'Your server does not support the connection encryption... - Gmail Help

In my case, after changing the registry key and rebooting, the accounts were back again....
No need to recreate them. Download went fine.

Experimental TLS1.3 should have been disabled.

Ref: What's new in Windows 10, version 1909 IT Pro content

Regedit-Security-SCHANNEL-Protocol-TLS1.3-Set Enabled to 0-16112019 071548.png
  1. Enter your Gmail account (click on Gmail in your browser).
  2. Proceed to the top right corner.
  3. Locate the gear icon and click on it to open the Settings menu.
  4. Go to the Forwarding and POP/IMAP tab.
  5. Proceed to the Enable IMAP option and select it.
  6. Make sure that the status says, ‘IMAP is enabled’.
  7. Save your changes.
Well done. It’s time to tweak your Gmail account security settings.
2. Allow less secure apps
In fact, your security settings might be behind the issue. Here is what you should do:
  1. Enter your Google account: navigate to the top right corner of the screen, click on your profile picture, and click on My Account.
  2. Select Sign-in & security. Then proceed to Connected apps & sites.
  3. Locate Allow less secure apps and enable this feature.
  4. Make sure to save the changes.
Your success is just around the corner, so keep working your way down.
Hope this helps you!
Hi; I spent ages hammering away at this for a customer (Outlook 2007, POP3, gmail), tweaking SSL and TLS in the registry, after having run SCANPST and corrected errors; the error was " (0x800CCC1A) : 'Your server does not support the connection encryption type you have specified." Nothing worked. So, I disconnected the PST file and rebuilt. (quit outlook, rename the PST, restart and let it create a new PST, reconnect the old PST (File, Open, Outlook Data File), move emails into the new folders, done). Everything was fine. So, despite the error message, the problem was database corruption (not fixed by SCANPST, of course), not with the protocols and transport.
I spent ages working on this for a customer (Outlook 2007, POP3, gmail), trying everything concerned with protocols; using regedit, tweaking SSL and TLS, recreating new email profiles, looking at the firewall, malware etc.; nothing worked. I had of course also run SCANPST. In desperation, I disconnected the PST file and created a new one, and everything was fine. I was then able to reconnect the old PST, and copy across the emails. So, it was just a case of database corruption, and despite the error message had nothing to do with encryption or protocols. And SCANPST didn't help. Lesson learned!
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