Calendar Month/Year Selection

When I click on GO to move to a specific month and year I am returned to my home page rather than the calendar for the selected month and year. Clicking the previous and next month selections works fine but using the text boxes to enter the month and year and then clicking GO always returns me to the home page. Is this a known issue or is it possible it is something I have done?

https://wordpress.org/plugins/rsvpmaker/