ipad synch needs computer authorized

I use my MacBook iTunes to manage the apps on my iPad. I downloaded another app and tried to synch the iPad. A popup claimed my Macbook (3.5 years old) needs to be authorized; I clicked on the window, provided my Apple ID and password and it was accepted. Back to the synch command and the iPad pops up the same window, need to authorize the computer. I go through the process again and get the reply "This computer is authorized". Back to the iPad and Synch, where I get the same popup to authorize the computer.

Any suggestions to fix this?

Ray