Can you please update to the latest version 2.2 of the Sign-up Sheet plugin and let me know if you still have this issue? If so, can you provide your System Information so I can debug further. You can find it by going to Sign-up Sheets > Help and copying/pasting the info in the big black box on that page. You can send it as a reply to this thread and just check the “set as private reply” before sending so that it will only be visible to Fetch Designs support.