Auth 2.0 Error 400 on Mail account

I FOUND THE SOLUTION.

People have mentioned it here, but with incomplete steps. So here is how to get it done:

1.) KNOW why this is happening in the first place: it's coz Google says your old mac and old mac OS have insufficient security. With that said, you can only update an old mac for about 7-10 years. Then you're SOL. Keep that in mind. Lucky for us old mac users (I'm running a 2011 MBPro with ElCapitan) -- we are still able to add new GMAIL accounts with a workaround.

2.) As mentioned here, open your GMAIL account preferences by signing into GMAIL by web browser and clicking on your avatar in the upper-right and selecting "Manage your Google Account". Then click on the "Security" tab on the left.

3.) Under "Signing in to Google" ENABLE 2-step verification. This alone will NOT fix it, but it WILL allow you use what Google calls "Less Secure Apps Access". If you notice in your account settings, Google automatically sets this to OFF -- essentially blocking access to any apps that Google dubs 'insufficient security'. Enabling 2-step verification will bring up a third line under "Signing in to Google" that says "App Passwords".

4.) Click on "App Passwords" and this will walk you through generating a password that you can use to manually add a GMAIL account with your old mac.

5.) Select and copy the generated password, go into Apple Mail preferences and select "other" when adding the new email account. Type in your gmail email address, and use the password you copied earlier, in the password field.

If this helps, PLEASE hit the kudos button to bring it to the top!

SOLUTION

In google, goto "Manage your Google account"...

On the left menu, select "security"...

Scroll to "2-Step Verification" (Mine was on already)...

Scroll to the very bottom of the "2-Step verification" page and select "App passwords"...

Select app menu, select "Mail" in the "Select Device menu, select "Mac"...

Click the "Generate" button and copy the password in the yellow box...

Open the mail app...

Archive your mail for the account you are fixing (if you need to, most people wont)...

Open system preferences from the Apple Menu...

Select "Internet Accounts"...

Delete the broken Gmail account here by clicking on it and hitting the - at the bottom of the window and close that window...

Go back to the mail app...

In the "Mail" menu, select "preferences" and add a new account with the + at the bottom of the accounts list making sure to select "other mail account" as the account provider and click "continue"...

enter the name for the account, enter the gmail email address, and paste the password you copied from the yellow box as the password.

TADA!

I could not, for the life of me, figure this out. The proposed solution still didn't work for me, but...

I found a solve

I noticed that the popup to login into google, when trying to add a new account, was opening in Safari Private Browsing mode. I went digging in Safari's settings, and in the "Advanced" tab under privacy I turned off the "Use advanced tracking and fingerprinting protection" AND the "Allow privacy-preserving measurement of ad effectiveness" and BAM... I was finally able to get past the 400 error that Google was sending back and I was able to authenticate and add my Gmail account to my Internet Accounts.

Hope this helps others.

When is Apple going to fix this? This is ridiculous. I hadn't changed my gmail password for years, but out of an abundance of caution - and all kinds of warnings about leaked passwords - I changed it. Now I can't use Apple mail on my mac? This should not be hard to fix, guys! Apple meet Google, shake hands, and fix this!

tnbriggs wrote:

But Apple do insist you buy overpriced new equipment from them at an alarmingly increasing frequency to have that security and privacy, thus ensuring their bottom line. And considering Apple's market cap is about twice what Alphabet's is, that seems to be working for them quite well, but less so for we poor consumers who can no longer afford to fund their greed.

That (bold text) is a non-sequitur. All of my Macs are expected to remain in productive service for a period of about seven years. The one in my office is nine years old, the one I am using at the moment is twelve years old, and I have others that are fifteen years old. They all work perfectly fine.

However, none of them have ever any Google products installed.

So your assertion that Apple insists upon purchasing "overpriced new equipment from them at an alarmingly increasing frequency" is demonstrably false.

Apple derives substantially all its revenue from selling hardware. Google derives substantially all its revenue from selling advertisements. Apple's single-minded approach to user privacy and protecting its customers' personal information is a constant irritation to Google. Why should Apple make it easier for them?

• If it is your desire to use Google products, then be prepared to replace your Macs every two to three years to keep up with its demands, which by the way have nothing to do with security and everything to do with their desire to harvest your personal information from your Macs, and sell it. You are the product Google sells. Presumably, your are being compensated for agreeing to that relationship. That's none of my business though. That's a private matter between you and Google.

• If you are required to use Google products, then buy a Chromebook. In fact Google should buy them for you, considering how much revenue they get from your voluntary use of their "free" services.

I also had the same issue on High Sierra. Do the following:

go to your google account settings, security tab and then app passwords. Select mail app on Mac device. Write down the generated password. Then on mail, click on add account, other mail account and type your email and the password you created in the previous step. That’s it 😉

FIX

Go in to yur google account

Select security

Go to App passwords

Select ap ( mail )

Select device ( mac )

Generate code

Copy code

Then go back to system pref and internet accounts

Add " OTHER ACCOUNT

put details in with copied password

BINGO !!!!

I also use High Sierra,
but in my case at the end of the procedure the MAIL app tells me that the account already exists.
I cannot remove the old Gmail account otherwise it will also be removed from the other devices
(iphone 14 and Imac)

Hi Guys, I managed to solve everything!

I have Macbook Pro 2011, Hig Sierra.

My steps were as follows:

1) I left the old gmail account disabled which didn't work.

2) Thanks to the system indicated above I logged into my Google account and created a new password for MAC and Mail.

3) On the Mac, in the mail app I created a new account by choosing "other" and writing my email with a dot before the @ (example: mymail.@gmail.com)

4) At this point I verified that the new account was working properly.

5) I re-enabled the old GMAIL account which no longer worked and... as if by magic it started working again!

6) At this point I deleted the new account I had created thanks to the "others" function

The old GMAIL account works fine!!

[Edited by Moderator]

Your solution was VERY helpful. I recently upgraded form OSX10.11 to 10.13 and was hit with the OAuth 2.0 Error

a small additional step to your #3.)step: after Enabling 2-step verification, the "App Passwords" did not show up on the "Signing in to Google" page. Instead, I had to click the right arrow at the far right side of the “2-Step Verification” line. That brought up a page titled "2-Step Verification" at the very bottom of THAT page is “App Passwords”

I was able to fix this ...

The trick is to go to the Security section of your account manager.

Then ... click on "2-Step Verification"

Then ... Scroll all the way down to App Passwords

Then ... follow the prompts to Generate a 16-digit key from Google.

Copy that key.

Then ... open Mail.

Click on Add Account

DO NOT click on Goggle

Click on Other Mail Account

Then ... type in your Gmail account

DO NOT type your usual gmail password

Instead ... Copy in the 16-digit key you got from google.

Mail should be working fine now.

To add to previous posting

Link below outlines some changes in Google regarding using Non Native Android Apps to access Google e-mail Services

The Application Specific Password factor was introduced not only in Google e-mail but also similar in Apple

Sign in to apps with your Apple ID using app-specific passwords - Apple Support

https://support.google.com/mail/answer/185833?hl=en-GB

I've used this technique in the past with success on:

1. 2006 Mac Pro 1,1 running El Capitan (hacked boot.efi)
2. 2011 Macbook Pro 8,2 running High Sierra.
3. 2009 Macbook Pro 5,1 running Catalina (patched).

And am about to try it again on a 2009 Macbook 6,1 running High Sierra. I'll keep you posted.

What I dont understand is that I am able to sign into one of my gmail accounts and Ive had 2fa on all my accounts this whole time and im just now getting this error. Im still able to sign in on my work Mac its just asks you to put in the code form the app. im not sure what they mean that it is not secure?

this is happening on my brand new Mac Book pro which I bought yesterday - everything is updated. So how can it be because it is old or outdated?