How to Fix macOS Mojave Fails To Authenticate Gmail Account

Updated to macOS Mojave but you still didn’t that Apple Mail will not connect to any of your Gmail accounts?

Then you’re not alone.

It’s infuriating to get the “Google requires completing authentication in Safari” notification where you would enter the right username and password but only to find be looped back to enter your Google password.

The loop is endless.. isn’t it?

This guide is written with this particular issue in mind coming across a few solutions to this problem on our own Macs, we can assuredly say that the issue is direct with my Apple Mail itself and not the device or your Gmail account.

We will go over the solutions step-by-step and help you fix this issue once and for all.

Let’s dive right in.


How to Fix macOS Mojave Fails To Authenticate Gmail Account: 3 Ways


1. Using Charles.

Thanks to a user, over at the MacRumours forums named Gannet, who came up with this solution.

The solution involved using Charles, a web debugging proxy application (you may or may not have an idea of what that means) but to sum it up it is one method of hiding your Mac’s IP address from any websites or apps that you visit. It is a helpful solution as it helps to determine where exactly a fault could be.

So now you know briefly about Charles, we will be using it to make it include your Gmail’s email address which is missing from Google’s own response side. The following steps closely follow the original instructions given.

Here’s how what do:

Step 1: First and foremost, you will need to download Charles, then proceed to install and run it.

Step 2: Once it is running and since this is your first time, then you will most definitely be promoted to authorize the automatic proxy configuration. Proceed with the on-screen instructions and ensure it is completely authorized. You can also make sure that the macOS proxy is also enabled and working properly.

Step 3: Great! Next, from the Help menu inside Charles, click on SSL Proxying and then Install Charles Root Certificate.

Step 4: Once the certificate has been installed, use Spotlight Search/Finder on your Mac and then look up your Keychain by simply searching for “Charles”.

Step 5: Open the Keychain, expand out the Trust section and make sure that the option under the Trust section is set to Always Trust. You will have to enter your password upon closing it.

Step 6: Now, jump back into the Charles application and from under the Proxy menu choose SSL Proxying Settings.

Step 7: Over here, you will need to add a new location with Host:

Step 8: Next, from the Tools menu, select Rewrite and then click to Add. Now there are two things you need to add here:

  • Add a new location with Host:
  • Add a new action with the following details:

Type: BodyWhere: ResponseReplace Value: //___________ add here Jake _____//


Step 9: Once you’ve added the above, make sure to Save it and you’re done. You can now proceed onwards to Apple Mail to authorize the Gmail account once again.


You can go ahead quit Charles, and delete the certificate from your Keychain if you wish to since the job has been done.


2. The Working Solution. (What Worked For Us)


The method that worked for us was actually, in fact, logging out from our Google Suite account then heading over to DisplayUnlockCaptcha to repair the access.


Here are the exact steps:


Step 1: Go ahead, open up Safari and then log out from your Google Suite account (to make sure you fix the right one)


Step 2: Next, head over to link to repair the access for the Google account. This is stated in the documentation by Google.


Step 3: Once you’ve repaired the access for the Google account, go ahead and add the account in your Mac’s settings (you can also do this via the Mail app).


Step 4: Lastly, verification in the newly opened Safari window will show up and from there you should be able to log in as your Gmail account should be authenticated.


3. Lightning Strike Icon.

This method was suggested by a user named Macendo after the user got in touch with Apple.

The user suggested that clicking on the sideways lightning icon which is located right next to your Gmail account that is offline should get the prompts to authenticate your Gmail account and then proceed to successfully log you in.

Here’s is what the lightning icon looks like:




4. Contacting Google Support for Help.

One of the tips given by our readers was to get in touch with Google’s support to resolve this issue.

As suggested by Google’s Support, what worked was that a workaround for the issue above managed to fix when authenticating the Gmail account:



You will also have to enable the Allow Less secure application setting in your Gmail web client in order for the below steps to take effect. (Add image)


What you need to do is delete/remove the Gmail account from your Mac’s settings or via the Mail app and then readd the account back as an IMAP account with the following format:

Username: your-full-Gmail-address

Incoming server:

Outgoing server:

This solution did not resolve the calendar and contact syncing part of the process.

Try it and see if it works for you.



5. Reset Your Keychain.

Another way to get around is to reset your Keychain Access on your Mac.



This solution will remove all of your saved Keychain passwords. Hence you will need to make sure that you back them up beforehand.


Here’s how you do it:

Step 1: add steps from page


6. Reaching Out to Apple.

— add from the other method go onto this #



7. Downgrade Your macOS Mojave to High Sierra.

One last option if you really despise the version of macOS Mojave and you want something with more stability and reliability then you may consider downgrading from macOS Mojave back to good ol’ macOS High Sierra.

Here are the steps (mind you it can be a little lengthy, but just stick with us and you’ll get it :)):

Step 1: Before you downgrade, it’s important that you back up your Mac to prevent your files and any important information from being lost in the process. Apple has written a great guide on how you can back up your Mac by using an inbuilt tool called Time Machine and it’s super easy.

Step 2: Once you’ve done backing up, you will need to download the macOS High Sierra installer file which is needed to downgrade from macOS Mojave. You can download the installer file using this link or directly from Apple’s official macOS Downloads page. Make sure that the installer file once installed is located in your Applications folder, we will explain why in a minute.

Step 3: Now you will need a USB drive (or pen drive as called in some places). Make sure that the USB drive has at least 15GB storage capacity. Get the USB drive and insert it into your Mac’s USB port. Make sure that you log in as an administrator to complete this downgrading process. Don’t know how to log in as an administrator on your Mac? There’s a guide for that too here.

Step 4: Next, you will want to write down the USB drive’s volume name when it shows up in your Finder. This is so we will need to refer to this name later. Also, make sure there aren’t any files or programs inside your USB drive that are important to you. Best to keep everything erased and start afresh.

Step 5: Time to downgrade! Go ahead click on your Spotlight Search and then lookup for Terminal.

Step 6: Next, go-ahead type in the following command into your Terminal. Take note that I had said it as type and not copy-paste directly because in the command the USB_DRIVE_VOLUME_NAME part needs to be substituted with your USB drive’s volume name you had written down in Step 4. Don’t hit enter yet!


Step 7: Now once you’ve typed it, it should look almost similar to mine. The command will erase the USB drive and will format it and then proceed to start copying the installation files onto your disk. You can hit Enter now and It should take roughly 15 minutes to complete (varies on your Mac model).

Step 8: Once the copying is done, you should see a Copy complete… Done. message as shown below. You can go ahead and eject the USB drive from your Mac.

Step 9: Now before we install macOS High Sierra, we first need to erase macOS Mojave from our Mac first. To do this, you will need to start your Mac into Recovery Mode.


How to Start your Mac into Recovery Mode

To do this, turn on your Mac and immediately press and hold Command (¥) + R keys together. Release them when you see an Apple logo and when requested, enter your password. Lastly, Startup is completed as you should be able to see the following utilities window. Proceed to the next step to find out which utility to click — Restore from Time Machine Backup, Reinstall macOS, Get Hell Online, Disk Utility.



Step 10: Once you’ve started your Mac into Recovery Mode (as shown above), you will need to select the Disk Utility then click Continue.

Step 11: From here, select your Mac’s startup disk from the left-panel sidebar and then select the Erase tab in the top menu (as shown below). Also make sure that under the format popup menu, you choose Format as macOS Journaled or APFS. Disk Utility shows the most recommended Mac format by default. We will be going with the APFS. Learn more about the right format types for your Mac here.

Step 12: Once that is done, click on the Erase button and then the erasing process will begin. When it is done, you can edit out of Disk Utility.

Step 13: Finally, we’re in the last section which is where we install macOS High Sierra onto our Mac. Let’s begin. Firstly, go ahead plug in the USB drive that you had created in the beginning Steps of this guide.

Step 14: Next, restart your Mac but it’s crucial that you press the Option key when it is restarting until the Install Disk shows up.

Step 15: From here, click on Install macOS High Sierra and then select Install macOS. Click Continue to proceed.

Step 16: You’re almost done. Next, Choose your main Mac’s Drive when prompted and continue with the process once again.

Step 17: Once the installation is complete, restart your Mac. You can use your Time Machine to restore from your backup to obtain all files and information back. Learn more about how to restore from Time Machine backup here.

Step 18: Lastly, verify that the installation is completed by checking the Installer log. To access the Installer log: Window > Install High Sierra menu > Installer Log. Alternatively, you can also press your Command (¥) and L keys together to bring up the installer log.


Done. ✅ You may breathe a sigh of relief.


  • Jake Kovoor

    Jake is the Editor-in-Chief of Saint and an independent software developer, with a Bachelors in Computer Science from Lancaster University, UK. He loves trying out various tech from the Flipper Zero to coding Raspberry Pis for automation. He started Saint back in 2016, having written over 100 posts, with the sole purpose of creating guides for software that had yet to exist back then to help users navigate around their technical problems.

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