The web site currently only offers you the option to select shops for your state of residence. A multi-state option will be added in the future. It indicates that you are not eligible for this shop at this time. It could be that you disqualified yourself by being late on a previous assignment. It may simply be that rotation requires a different shopper.
Clients vary in their requirements for shoppers.
Some do not allow you to visit the same location within a specific time period. All shops for which you are eligible are shown on the website. It is quite possible you will qualify for this assignment next month or the month after, so check back regularly. The top part of the right side of the screen will show available opportunities. You might have to scroll down to see all the information.