Still having issues with Apple Mail

It will not recognise my Yahoo Mail password for one of my accounts. Keeps asking me to enter the password and saying it cannot access it.

I've tried removing it and re-adding it in, no effect. Same thing over and over again. It is the correct password. As I can access the web based Yahoo Mail with the same username and password and have no issues with it.

If any of you could advise me on how to effectively resolve this I would appreciate it so much. Thanks

Edit:

By the way I'm using version 6.2 and I am using Mountain Lion as my OS