Please help, Mail problem

Hi everyone, im new and i have a problem with my mail. I'm on a macbook pro that i got in december. anyways i haven't been able to receive or send mail for about a week and a half. i had my mail in my dock synced with my gmail account. for some reason my mail account won't go online. so i deleted it and tried to sync it again but now it is saying that my password for my gmail is wrong. however when i go to gmail.com i am able to access my gmail with the same password that i am putting into my mail for my mac. i have no idea why my mac mail isn't accepting my password. also my gmail is synced with my iphone mail and everything is working fine. whats going on?!?!?

now my iphone is saying my password and username don't match up. however i go to gmail.com and my username and password are the same as i put into my macbook pro mail and my iphone mail and it works just fine. i'm so confused

Well if you are using gmail in mac mail try right right clicking on your gmail account on the left side of mail and see if it says "take gmail off line". A friend of mine had the problem yesterday with his aol mail not receiving in the Mac mail but was able to get it in the webmail. The request for password was also showing up. His was off line and when he corrected it the gmail came thru fine. If this is like your problem then it should work also.