Welcome to the forum, romanbenedict. I’m sorry you’re having this problem. I recall it has happened once or twice in the past, but I’m not sure what the cause was. Removing the saved audio engine data from your project should be sufficient to fix the problem. The steps to do that (a bit fearsome, I’m afraid, but doable) are described here.
If you find yourself unable to follow the steps, please feel free to zip up the project and attach it here, and we’ll be able to make the fix for you.