Oops! We moved too fast. Happens to the best of us.
Perhaps it wasn't us who moved too fast, but instead there was a regression somehow with our dog. The weather, a dodgy tummy from that scavenged street-meat, a thunderstorm, or an altercation at the dog park.
Whatever the reason, we just take it as information and recognise that our dog needs "easy" for a day.
My go-to is to go back to the previous Mission and repeat that level once. If your dog had a really rough day, make life really easy for them and repeat an earlier Mission.
The most important thing is to not get discouraged. This is a really difficult concept for our dogs and every step is money in the bank!