Make sure your
phone has the correct date, time and is set to the correct zone using
Network time.
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.
If you have a removable
battery pull this 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. If you are using the Email
setup folder and have chosen Google then only add your user name (stop
before the @ symbol)
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.