Today I've to resolve one issue for user that Company used Outlook sync with Google Apps unable to Send/Receive in outlook.
Outlook keep prompting to key in username and password for POP/SMTP server login.
I'd key in the password many times that give by affected user but not login successful.
I asked user to ensure the password is correct or not. User answer then that she change her Google Mail Login to 2-step verification for good security at last week.
That's the answer!
If you have already used Outlook, you will not be able to receive emails after enabling the 2-step verification feature.
That is because you added 1 more password layer and Outlook or other email clients can’t ask for verification codes now.
So, to make it work properly, you will need to create an application-specific password and use it in place of your normal password.
Here is the steps to generate the application-specific password for Outlook.
Visit to below link and login with your google username and password.
Click Generate Password if you see the page shown below (take note the below picture is only portion of whole page)
Copy the password appears in Field and update in Outlook.
Bravo! Your Outlook back to work.
May you all be happy.
(Be knowledgeable, pass it on then)