In case you have a debt from a previous period (11 March), Neptun might block your registration.
What can you do in this case?
Take your exams without interruption!
Website:
https://www.lib.pte.hu/en/take_your_exams_without_interruption-340
Blog: https://my.lib.pte.hu/en/we-help-you-so-you-can-take-your-exams-without-interruptions/