iPhone wont accept wifi password from Airport Extreme!

Hello applebuddies!

I am having an issue that is ongoing with my iphone and sporadic with my ipad.

I have always been able to connect to my network with both my iphone and ipad, however, just recently, every time I try and connect to my network--error message "incorrect password" or "unable to join network" pops up.... I know the password I am using is correct, and occasionally my ipad will accept it but kicks me off the network after a while. My apple tv and macbook both are working on the network fine, as well as my work PC.

I haven't changed any settings or anything, this has just happened.

Can someone help me out here?!?!?!