Cannot add Gmail Account to Outlook anymore

I was having the same issue trying to get Outlook 2016 to connect to my gmail account.  I ensured my gmail was IMAP enabled and Allow Less Secure Apps turned ON.  Still nothing, yet it worked elsewhere (mail client in Windows 10, web, etc...)

I finally found the work around, which suggests its a bug in Outlook 2016's gmail setup.

The bug is only encountered going through the "Add Account", where you get the screens noted above but can't enter all the other information we used to enter.

You actually need to go through "Account Settings" -> "Manage Profiles" and add it through that window.  It will bring you to the old style screens instead of the one above. 

My steps:

1) Open Outlook 2016

2) Click the File tab

3) Click on "Account Settings"  and choose "Manage Profiles".  Do not use "Add Account"

4) You may be asked if you want want this app to make changes. If so, click "Yes"

A new dialog box will open.

5) Close Outlook 2016

6) In that dialog box, choose "Email Accounts".

7) Go through the process of adding an IMAP account as normal, specifying everything you need to for your Gmail account (info can be found in google if needed).

After I entered everything correctly, it tested and created successfully.  I opened Outlook 2016 again and now I can get my mail.

Hope this helps.