The verification is mandatory and can be taken on three dates, in September, October and November.
You can confirm enrollment, attend classes and take in-progress tests even if you have not passed or have not yet taken the verification.
If you do not pass the verification (or if you do not attend any of its three editions) you will be given Additional Educational Obligations (OFA) which you can fulfill by December through a self-training online course and by passing a verification (TE.S.E.O.) for which there are 3 editions.
If you have not yet made up the OFAs by the end of December, you will have to take some first-year exams as a priority and, until you have passed at least 12 CFUs of those exams, you will be prevented from taking the other exams.
If, at the beginning of the second year, you have not yet made up your OFAs, you will be able to register for the second time, but as a repeater, and will not be able to plan to take teachings from years beyond the first.