I got a message saying that software was not purchased on this computer and to reenter apple id and password. I actually purchased software on this computer. When I enter apple id and password, the software will no longer work.

I have been using a recipe program (YummySoup!) and it has worked fine until yesterday. The program has not been updated on the App store for several years, but still worked with all versions of OS X. Yesterday I backed up my computer to Time Machine as normal. After that, when I tried to open YummySoup!, I got the message Software Purchased on another computer, reenter applied and password to use software on current computer. I actually purchase the software on this computer. After I entered my apple id and password, the software no longer works. It says it opens but does not - nothing happens. If I do a get info on the app, it says the software is open, but it is not. All other software seems to work just fine except one other program that gives the same message about being purchased on another computer. I'm reluctant to enter apple id and password for fear of the same thing happening.