Mail, Contacts & Calendars refuses to connect to Google Since yesterday the System Preferences pane on Mail, Contacts &amp; Calendars refuses to connect to Google to setup e-mail, calendars and contacts. It started after Contacts.app did not want to sync with Google Contacts and asked and refused my correct password. After that Mail.app and Calendar.app did the same. I removed the account from System Preferences and attempted to start anew. 

However, now it throws the following error at me: 



Nowhere in any log I know can I find more information on the error. When I monitor the connection using Little Snitch it shows that the following connections are attempted:



I can ping them all through Terminal.app successfully.

I have no 2-step verification, so I'm not using application specific passwords in Google.

This is what I've tried, all without a positive outcome:


Add a Gmail account in the Guest user (same error).
Make a new Gmail account, try to add it (same error).
Enable 2-step verification, make application specific passwords (same error).
Run Keychain first aid.
Verify &amp; Repair permissions.
Verify &amp; Repair disk (volume bitmap needed minor repair for orphaned blocks). After repair still the same situation.
Reverted /etc/hosts file to default.
Disabled Little Snitch.
Boot from external drive into Yosemite, try to add the Google account.
Try connection through ethernet instead of airport express.
Try connection through a different network entirely.
Following the troubleshooting steps from Google.
Allowing "less secure application" (that still use OAuth 1.0) to login to Google.  
Resetting the Keychain


I've really exhausted my Google-fu and little knowledge I have on Macs. I would really appreciate some pointers on where to look further.
According to this Gmail help forum thread this is an issue that is fixed in Mac OS 10.10.3. There user jbrandtAUS writes on the 29th of May:


  From others I have talked to, starting yesterday, people have not been able to add their Gmail accounts to Mail or System Preferences > Internet Accounts if they have 10.10.1 or 10.10.2... if you update to 10.10.3 it will work


So the solution is to upgrade to anything above Mac OS 10.10.2.