Several users have reported getting an error message, that says “The user name or password for Gmail is incorrect,” when trying to access Gmail on an iPad, iPhone, iPod or iMac.
The problem arose because Gmail uses different techniques to try to stop spammers. Setting up an account on a mobile device can trigger it to be locked. To unlock the account, you must visit the following link and prove you are human.
https://www.google.com/accounts/DisplayUnlockCaptcha