Can not Update App from App Store
I have Tweetbot installed & it needs an update. When I check my purchased apps in the store it shows an update is available. However, when I hit the button it asks me to sign in with the account that I used to buy the app, which is the app I am signed in with. I do not get an error code just a message stating "To update this application, sign into the account you used to purchase it." Can anyone tell me how to solve this issue?
MacBook Air, OS X Mountain Lion (10.8.4)