Cannot add Gmail to Outlook: This browser or app may not be secure.

Question

I'm trying to add my Gmail account into Microsoft 365 Apps for Enterprise Outlook version 2104 build 13929.20254 Click-to-run 64 bit. I go to File --> Add Account --> enter my gmail.com address and click connect. Another screen pops up with my email address pre-populated and I click Next, which brings me to this screen:
Couldn't sign you in
This browser or app may not be secure. Learn more

Try using a different browser. If you’re already using a supported browser, you can refresh your screen and try again to sign in.

We've modified a lot of Windows Internet Settings, but I can access Gmail through IE and my default Edge Chromium browser. So why doesn't it work when accessed through Outlook? Outlook appears to be using some version of IE instead of my default Edge browser. Does anyone know why that is, or exactly what setting needs to be enabled for this to work?

Thanks.

Answer 1

Hi @Alex Carlock I Have Finally Solved This issue "Couldn't sign you in This browser or app may not be secure. Learn moreTry using a different browser. If you’re already using a supported browser, you can refresh your screen and try again to sign in."

Actually its an issue inside microsoft edge not in your outlook... First you need to go to your computer Settings > Default Apps > Default Browser and then select Microsoft Edge as your default browser,

if you already have Microsoft Edge as your default browser then you can skip this step... After doing this, now go to Microsoft Edge and Type this text below in the address bar....

edge://settings/defaultbrowser

Like in the screenshot below i have attached... ******Now see the option "Allow Sites to be reloaded in Internet Explorer Mode (IE MODE)" Select Don't Allow and now Go to Outlook and Add Your Gmail Account, Now it should not give any problem. I Hope this will be helpful

Answer 2

I had the same issue when launching my app using VS 2022.

For me it was related to Script Debugging (Enabled). I disabled Script Debugging and it worked.

Answer 3

https://www.slipstick.com/outlook/outlook-errorgoogle-sign/

all done.

Answer 4

1. I was able to fix the issue by login into the Gmail account going to security(https://myaccount.google.com/u/0/security) and setting up a PASSKEY for Gmail security on the computer needing Gmail added on to Outlook.
2. Then go to Outlook->File->Account settings and add the Gmail account as usual

Answer 5

OK, I am updating multiple sites that were dealing with this same problem. As seen in THIS entire thread, there are multiple things that might work for you. I tried them all, and none worked for me until I found THIS, which DID, from official Microsoft:

https://support.microsoft.com/en-us/office/unable-to-sign-in-or-add-a-gmail-account-to-classic-outlook

And then I used the second of the posted options, in an elevated Terminal

https://learn.microsoft.com/en-us/microsoft-365-apps/insider/deploy/registry

And I have Office Professional Plus 2021 rather than 365. It's STILL "Office 16" in programs, but I didn't have a 16.0 in my registry setting under the appropriate "Policies" setting, but I ran the command anyway, and it created a 16.0.

I then restarted Office, and checked for updates, which I had just done earlier. I found a new one, took awhile to download and install, I crossed my fingers, and voila: I'm a member of the Beta community and on the beta track. I proceeded to try adding a gmail account again, and THIS time, it opened and external browser window, rather than the built-in...I signed into google, and DONE.

Wow, I really didn't have four hours to figure this out, and my gmail is just an account that I use for junk, but my psycho cousin has been blocking my other email and I needed to get through to her, and I HATE using web mail..

Have a Great day!