There is no expiry period for the Coaching Completion Certificate (CC) also.
However, the student whose registration has been cancelled on account of the expiry of the 5 year period subsequent to registration will not be permitted to attempt the examinations until he/she gets their registration revalidated by de novo registration.
Failing to get through within the maximum limit
If a candidates chances of making an attempt at the examination are exhausted on account of the registration getting expired the candidate has to get his/her registration renewed. Renewing the registration would put him/her in the same state as if his/her registration were valid and in force.