Try the instructions below but some countries have restrictions on Google and/or Blackberry so have any of your friends got the same problems or are they able to sign in?

If you have decided to use Two Step then you need to get a specific validation code for your phone and this will repeat every thirty days. You then need to enter the new verification code  and then do a second attempt using the normal password should the phone not remember this. If not:

You can try the Captcha page https://www.google.com/accounts/DisplayUnlockCaptcha from the phone's Browser

Other reasons for not being able to log in:

Occasionally, because of a font setting the first letter of a password gets capitalised so you could try typing the first letter twice and deleting the first of these.

A new possibility is that you now need an eight letter/digit password and seven letter/digit passwords are not being recognised.

If not then try:

In your pc try going to the bottom of your Inbox page and Last Account Activity - Close all other Activities and then sign out of Gmail including the iGoogle page.

Now pull the battery in the phone and give it as much time as you can spare before putting it back in and allowing the reboot. Try signing in now retyping in your full address including the correct Gmail/Googlemail. com and the password making sure it is exactly correct. Might take a couple tries but it should get there as this works for most applications.

One further problem could be if your keyboard is set to the wrong language which needs to be the same as when you originally created the account. This can be caused through an OS update.