Cron Expression for AWS SSM Statemanger

Question

For AWS SSM state manager association, I have a cron expression to fire at 23:00 hours on every 14 days as below.

cron(0 23 1/14 * ? *)

On saving the changes, it gives error as: InvalidSchedule: Schedule expression cron(0 23 1/14 * ? *) is currently not accepted

Thanks for your help.