Gnome online accounts and google gmail two step verification

If you are stuck in authenticating your gmail (google) account with Gnome's 'Online Accounts', here's the quick solution to resolve it.

Prior to that you have to create an application specific password for this authentication.

Follow the following steps OR use this link directly.
Manage your application specific passwords

1. Go to https://www.google.com/settings/account
2. Select 'Security' from left.
3. Scroll down to '2-step verification' and select 'Manage your application specific passwords'.

Then

• Enter a name for in the field and 'Generate password'
• Keep the generated password copied somewhere or in the memory.

• Go to 'Online Accounts' in Gnome and add your google account using your login password (not the generated one).
• Now go to 'Passwords and Keys' application (also know as Seahorse).
• Search for 'GOA google' and your specific account you just added above.

• Get properties and click show password.

• At the end of that string, you can find your password as "'password': <'your password'>". Replace 'your password' with the generated password above.

• That's it. You're done with the authentication.

As a last note, if 'Online Accounts' is still trying to connect without success try logging out from your Gnome session and logging back in.

Have fun!