I recently enabled 2-factor authentication in Gmail. I have two computers running, and I setup Google Talk and Outlook on both to use the app password. I also enabled my phone to use the app password.
I have a rogue application out there that is requesting access every 28 minutes, which means I get a text message every 28 minutes. Is there any way I can tell which application is requesting authentication?
There should be a name on the requesting page somewhere. Other than that, if you want to, you can grant access and then go to the Google dashboard and see what app it is. It is a bit of a risk since you don't know what app is asking. But normally it's something you already use.
Go to https://www.google.com/dashboard/ and sign in (if you're not already) you should see a link under your email address that says Websites authorized to access the account or you can go to Manage account and then select edit on Authorizing applications & sites. It should be on the list then.
That's my best suggestion.
