Solved GMail + Outlook 2016 fail

TerryG · Mar 13, 2026

I changed my Google password, then Outlook quit picking up my Gmail. I've been trying for days to reestablish Gmail with Outlook but every attempt fails. Every attempt seems result in of the attached errors.

Can you help me with this?

FreeBooter · Mar 13, 2026

I have same problem see updating Outlook will help other than this i have not found any solution for this problem.

z3r010 · Mar 13, 2026

I thought Gmail stopped supporting Outlook 2016 with standard authentication years ago. Are you using Gmail app passwords to log in instead of your regular Gmail password?

TerryG · Mar 13, 2026

z3r010 said:
I thought Gmail stopped supporting Outlook 2016 with standard authentication years ago. Are you using Gmail app passwords to log in instead of your regular Gmail password?

I've been using Outlook 2016 for years with Outlook without any issues, but I haven't needed to change the password for years. I am not using app passwords but I did explore that without success.

Looks like I need to update Outlook.

z3r010 · Mar 13, 2026

Try getting an app password from gmail for it, I'm a bit busy now to go through it, but I've just got grok to do some instructions.

Instructions: Generate an App Password for Gmail

Important prerequisites

You must have 2-Step Verification (2FA) turned on for your Google Account. App passwords are not available without it.
If you don't have 2-Step Verification enabled yet:
1. Go to Sign in - Google Accounts
2. Under "How you sign in to Google", find 2-Step Verification → click it → follow the prompts to set it up (usually with your phone number or authenticator app).
Note: App passwords are a legacy feature for older apps/devices (like Outlook 2016 with manual IMAP). Google prefers "Sign in with Google" (OAuth) where possible, but this still works reliably in 2026.

Step-by-Step: Generate an App Password

Sign in to your Google Account
Open a web browser and go to: Sign in - Google Accounts
Log in with your Gmail address and password (use your normal login here).
Go directly to the App passwords page (easiest way)
Visit this link: Account settings: Your browser is not supported.
- You may need to re-sign-in or confirm your identity.
On the App passwords page, you'll see:
- Two dropdown menus (or fields): Select app and Select device (or a text field to name it).
- For most cases (like Outlook):
  - Select app → choose Mail (or "Other (Custom name)" and type e.g. "Outlook 2016").
  - Select device → choose Windows Computer (or "Other" and name it e.g. "Desktop Outlook").
- If no dropdowns appear, look for a Generate or Create button/area.
Create the password
- Enter a custom name if prompted (e.g., "Outlook IMAP" – this helps you remember later).
- Click Generate (or Create).
- Google will show a 16-character code (e.g., abcd efgh ijkl mnop – spaces are for display only).
- Copy this code immediately (highlight and Ctrl+C).
- Important: Once you click Done or close the window, you cannot view it again. If lost, generate a new one (old one stops working).
Use it in your app (e.g., Outlook)
- When setting up/adding the Gmail account:
  - Username: your full Gmail address (e.g. john@example.com)
  - Password: paste the 16-character App Password (no spaces, not your regular password)
- Server settings (for manual IMAP):
  - Incoming:
    Code:
    imap.gmail.com
    port 993 SSL/TLS
  - Outgoing:
    Code:
    smtp.gmail.com
    port 465 SSL or 587 STARTTLS

FreeBooter · Mar 13, 2026

Microsoft investigates classic Outlook sync and connection issues

Microsoft is investigating several issues causing email synchronization and connection problems when using the classic Outlook desktop client.

www.bleepingcomputer.com

TerryG · Mar 13, 2026

FreeBooter said:
Microsoft investigates classic Outlook sync and connection issues

Microsoft is investigating several issues causing email synchronization and connection problems when using the classic Outlook desktop client.

www.bleepingcomputer.com

The second paragraph seems to address my issue exactly. Who knows if MS will fix it, I just read support ended October 14, 2025.

TerryG · Mar 13, 2026

z3r010 said:
Try getting an app password from gmail for it, I'm a bit busy now to go through it, but I've just got grok to do some instructions.

Instructions: Generate an App Password for Gmail

Important prerequisites

You must have 2-Step Verification (2FA) turned on for your Google Account. App passwords are not available without it.

If you don't have 2-Step Verification enabled yet:

Go to Sign in - Google Accounts

Under "How you sign in to Google", find 2-Step Verification → click it → follow the prompts to set it up (usually with your phone number or authenticator app).

Note: App passwords are a legacy feature for older apps/devices (like Outlook 2016 with manual IMAP). Google prefers "Sign in with Google" (OAuth) where possible, but this still works reliably in 2026.

Step-by-Step: Generate an App Password

Sign in to your Google Account
Open a web browser and go to: Sign in - Google Accounts
Log in with your Gmail address and password (use your normal login here).

Go directly to the App passwords page (easiest way)
Visit this link: Account settings: Your browser is not supported.

You may need to re-sign-in or confirm your identity.

On the App passwords page, you'll see:

Two dropdown menus (or fields): Select app and Select device (or a text field to name it).

For most cases (like Outlook):

Select app → choose Mail (or "Other (Custom name)" and type e.g. "Outlook 2016").

Select device → choose Windows Computer (or "Other" and name it e.g. "Desktop Outlook").

If no dropdowns appear, look for a Generate or Create button/area.

Create the password

Enter a custom name if prompted (e.g., "Outlook IMAP" – this helps you remember later).

Click Generate (or Create).

Google will show a 16-character code (e.g., abcd efgh ijkl mnop – spaces are for display only).

Copy this code immediately (highlight and Ctrl+C).

Important: Once you click Done or close the window, you cannot view it again. If lost, generate a new one (old one stops working).

Use it in your app (e.g., Outlook)

When setting up/adding the Gmail account:

Username: your full Gmail address (e.g. john@example.com)

Password: paste the 16-character App Password (no spaces, not your regular password)

Server settings (for manual IMAP):

Incoming:

Code:

imap.gmail.com

port 993 SSL/TLS

Outgoing:

Code:

smtp.gmail.com

port 465 SSL or 587 STARTTLS

Wow! Great response. Thanks.

hader · Mar 13, 2026

First off all;
Make a copy of the now troublesome gmail.ost file at C:\Users\<user>\AppData\Local\Microsoft\Outlook. Save it at an other location.
Then use the online version of gmail. Log out, log in and check if your current username and password is valid there.
Something may have happened during that change old-new password.
If you can logon inside the online version without any problems and not inside outlook; If it uses the old password than that make sense why it did not work.

Change the password inside that outlook - gmail account.

With Outlook 2021 that is more troublesome.... Account settings - Manage Profile - Show Profile - Property's - Email accounts - Goto the gmail one - Change password or test it first... Ehrr.... I see the same issue (does not recognize my current password also. Online Gmail says it is OK.) now as you have also... So cancel..... I received a recent Windows update last week ago... Is that????....* See if an update for Outlook is waiting?..... Surprise! Yes there are!!.... Done. Closing Outlook 2021 and try that password testing again..... Still these same error. Why? Cancel that then and check if can update the current gmail map inside Outlook. It does.... I find this strange. I suspect some Windows update is responsible for this. Looking at this forum and just searched "Outlook 2016" I see now many the same complaints from you but from other users also...... Something smells fishy here..... It's not Gmail. It still supports Outlook 2016...

My god.... I think now it's the time to switch to Thunderbird........

If nothing helps: I would just delete that account and make a new one. What setting you have to use inside outlook just use these settings;

Key Settings for Gmail in Outlook:
Username: Your full Gmail address (username@gmail.com).
Password: Your Gmail password or App Password.
Incoming Mail Server (IMAP): imap.gmail.com
Incoming Port: 993
Incoming Encryption: SSL/TLS
Outgoing Mail Server (SMTP): smtp.gmail.com
Outgoing Port: 587 or 465
Outgoing Encryption: STARTTLS or SSL/TLS
Authentication: Requires authentication (Yes)

Steps to Configure (General):
Enable IMAP in Gmail: Go to Gmail Settings > Forwarding and POP/IMAP, and select Enable IMAP.
Add Account in Outlook: Go to File > Add Account (or Account Settings in older versions).
Enter Details: Enter your Gmail address, select Manual Setup (if needed), and enter the IMAP/SMTP settings above.
Security: If you have 2-Step Verification enabled, generate and use an App Password.

You are still left with the old gmail.pst file so everything is still accessible in there. Don't throw that one away!!!. You can import that now offline old gmail mailbox later. It will start to make a newer gmail .pst file. The new gmail entry is getting filled with stuff it will find on the server.
Compare the outlook gmail maps and emails inside the old an new one. If they are the same; Throw the old gmail .pst into the bin. If not; transfer them from the old to the new and then throw the old one into the bin.
Goodluck.

Jorgen E · Mar 13, 2026

I have just been there with my Outlook 2024 - by accident I deleted the allowed acces in Google account.
You have to allow acces for Outlook on your Google account
In account settings in Outlook I thoose to repair it (manual), and it automatically took me to my Google account,
where I could allow Outlook acces. I was loged in on my account via Chrome.

Share some access to your Google Account data with apps from other developers - Google Account Help

To unlock certain features, you can give apps from developers other than Google some access to your Google Account data. For example, a photo editor app may request access to your Google Photos to app

support.google.com

Hornblower409 · Mar 13, 2026

There are two Microsoft Support Articles (with workarounds) that may apply to your case:

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

Unable to add a Gmail account to classic Outlook - Microsoft Support

The article title is "Unable to add a Gmail account ..." but I have seen reports that this bug can also cause working GMail accounts to fail. The fix is the same - Clear the Windows Credentials.

Microsoft Q&A on this issue with feedback from Microsoft Support:

Can't add gmail to Outlook - Microsoft Q&A

Gabe Bratton Microsoft Employee Mar 9, 2026, 3:11 PM - We are escalating a bug for this issue

Steve C · Mar 14, 2026

Gmail is now failing for me in Outlook on 2 PCs. Is this an issue with Gmail they are going to fix?

Hornblower409 said:
There are two Microsoft Support Articles (with workarounds) that may apply to your case:

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

Unable to add a Gmail account to classic Outlook - Microsoft Support

The article title is "Unable to add a Gmail account ..." but I have seen reports that this bug can also cause working GMail accounts to fail. The fix is the same - Clear the Windows Credentials.

Microsoft Q&A on this issue with feedback from Microsoft Support:

Can't add gmail to Outlook - Microsoft Q&A

That MS QA fix worked for me. Who has messed up this time MS or Google?

TerryG · Mar 14, 2026

I cannot believe how helpful this community has been. Is this even the internet? Ha, ha.

Many thanks to all.

Hornblower409 · Mar 14, 2026

Steve C said:
Who has messed up this time MS or Google?

Microsoft.

Steve C · Mar 15, 2026

TerryG said:
Wow! Great response. Thanks.

The bug in question results in the user never being prompted for a password so this fix will not work

Sassofalco 80 · Mar 15, 2026

Hornblower409 said:
There are two Microsoft Support Articles (with workarounds) that may apply to your case:

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

Unable to add a Gmail account to classic Outlook - Microsoft Support

The article title is "Unable to add a Gmail account ..." but I have seen reports that this bug can also cause working GMail accounts to fail. The fix is the same - Clear the Windows Credentials.

Microsoft Q&A on this issue with feedback from Microsoft Support:

Can't add gmail to Outlook - Microsoft Q&A

Thank you so much for your clear work-around guidance, with resultant subsequent successful "restoration" of my Gmail Account, back again in with the Outlook "bucket" contents - lost all my hair during the process, but it sure did work for me. Cheers, and many thanks again. Fix found here -

Unable to add a Gmail account to classic Outlook | Microsoft Support

Unable to add a Gmail account to classic Outlook

support.microsoft.com

Steve C · Mar 15, 2026

Sassofalco 80 said:
Thank you so much for your clear work-around guidance, with resultant subsequent successful "restoration" of my Gmail Account, back again in with the Outlook "bucket" contents - lost all my hair during the process, but it sure did work for me. Cheers, and many thanks again. Fix found here -

Unable to add a Gmail account to classic Outlook | Microsoft Support

Unable to add a Gmail account to classic Outlook

support.microsoft.com

We have worked this out thanks to this forum but there must be millions of people working out how to fix this problem due to another epic failure of software engineering thanks to Microsoft.

Solved GMail + Outlook 2016 fail

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