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 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.

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 !!!!

Bob, after having deleted your Google account (macOS System Preferences, Internet Accounts), add a new account by selecting "Add Other Account…". Then you can configure your Gmail account by entering your gmail email address and the app password that you created by following the solution described in this thread.

Google seems to have made a change in being more struct regarding security. Apple Mail on High Sierra is pretty old and no longer considered as "secure" by Google. Therefore Google started to block logging into your email account with your regular password.

The workaround is, that you generate a password only to be used for the mail application and nowhere else. Also not storing it on your computer! Whole point is to no longer having to use your regular password on for Apple Mail as it potentially can get hacked. You still can use your regular Gmail password from your phone or through Web. Just the now "insecure" Apple Mail app should use this separate app password to isolate potential damage.

Hi YvonnePhoto

I'm not affiliated with Apple nor with Google, but this authentication issue is a common issue in the IT industry and not at all specific to Apple hard- and software.

Please follow the instructions from jrginnyc - this is the proper approach to implement a work around. It is that Google has increased security measures and no longer allows the use of the standard Gmail password for all software no being up-to-date security wise. For instance my HP printer imposed the same issue as it is using my Gmail account to deliver me the scans per Email.

All Google is asking is, that you specify a separate - so called app password - that you only use for a dedicated purpose, in this scenario Apple Mail on our desktop or laptop. Then you configure an "Other account" (not Google) but provision your gmail address along with the application password and you are good to go. I just had to do it on my wife's PowerBook which still runs High Sierra.

Alternatively you can also consider using Mozilla Thunderbird on your Mac. You only have the issue on your Mac as Apple tries to simplify the setup process for Gmail and this is a built-in feature of macOS which is no longer supported with updates from Apple. If you still run Windows XP or Windows 7 wyou would experience similar issues.

Hope that helped providing some background to the topic. The process described above will be working 100%. Let me know if you struggle and need further support. You definitely can continue using Apple Mail on your legacy Apple hardware for Gmail.

The workaround works, the thoughest part is finding the app password generator in Google's kitchen-sink account.

Your Mac and thus email client (Mail) is probably too old to comply with Google's security policy so you are unable to add gmail account to Mail with default procedure (using Google authorisation site where the error message appears). You need log in to your google account, enable 2-step verification if you haven't done that yet, and generate an app password (for Mail). Then in Mail you choose "Other account" (not Google) and use the generated password there instead your standard Google password.

This works! Once you've enabled 2 factor, then click on App passwords, dont click on 'google' check box when adding the account, click on other and in the password section, dont type your gmail password, enter the 'generated app password' and it adds it as normal.

I had this because I signed in on a windows laptop with my google account and it all went to crap on my mac.

This fixes it.

Thanks for the help!

I had this exact issue on High Sierra.

What worked for me was step two here:

https://technclub.com/guides/fix-oauth-2-0-error-400-apple-mail-mac/

Sign in to google on a browser (I used Safari as suggested by the above link).

Go to 'Manage Your Google Account'. Then 'Security' from the sidebar.

Under 'How you Sign In To Google' go to '2-Step Verification'.

Down the bottom of this page is 'App Passwords' where you can generate a one-time password. Do this and copy it.

Back to Mac Mail and instead of selecting Google under 'Accounts', select 'Other Mail Account'.

Then enter your gmail email address and the one-time password.

This worked for me so I hope it does for you too.

Cheers.

Finally managed to get round this today.

Goto the security option at https://myaccount.google.com

• Enable 2 factor authentication

• Once enabled there is a "App passwords" option on the 2FA page (https://myaccount.google.com/u/8/apppasswords)

• Create an app password for Apple Mail. It will then give you a 16 digit code to use in Apple Mail. (Note that if you copy and paste it will include the spaces between the blocks of 4 digits)

• Use this password in the IMAP/SMTP settings

After that, login to Gmail and goto the pop/imap settings

https://mail.google.com/mail/u/8/#settings/fwdandpop

• Enable IMAP here

Return to Apple Mail

• Sync you email and it should all work fine.

One missing element of the steps outlined in the link is that when you create the App Password, copy it and then go to your Apple Mail app, add account and go to "Other Mail Account" (do not try to add Google Account again or you will continue to get the same message), type in your Google account address and when it asks for a password paste in the App Password that was generated by Google and it will set it up.

edmeyers wrote:

where do i find app passwords.......i'm not seeing it unfortunately but it could be old age

Google Account Help – Sign in with app passwords

You log in to the Google site, and ask Google to create the app password. Then you use it with Mail on the Mac. Note that Google will not generate an app password for you unless you turn on 2-Step Verification.

The Animaster has the solution. Well it's not the easiest thing I've ever done but IT WORKS! I copied it just in case I can't get back to it so here it is. The only down side is your gmail on macmail does't connect to the mac calendar. Here is the Animaster SOLUTION & IT WORKS. Don't let the 2 step verification scare you, it's just what it's called & you only do it once to get it to work. Here it is from the Animaster:

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!

Reply Helpful (116)

I fixed this...

I went to google settings > security > 2-step verification > app passwords > type in imail and generate a passcode, copy the passcode. Then I went to iMail > add account > select "other mail account" > type in email address and the passcode that was generated with google. Hit enter and it should work.