You can try again later. When people cancel their reservations before the ticket sales period is over, the tickets again become availble. (ex. 13 Dec had been sold out on Tues but 4 spots opened up before Thursday noon.)
Here are some instructions to help you with the registration process.
(An example: https://lhcfp.dol.ca/registration-st-peter-goderich)
If you have any questions, please feel free to contact us.