I can't subscribe to student offer

[Amaury6]

Hello,

I am currently using the basic premium offer (9.99€) but I have seen that there is an offer for students. As a student, I wanna change my offer and subscribe to the student one but i can't. 

The fact is that it is continually loading when I have to enter my credit card number

I just can't do something and that's pretty annoying. 

I have added a screenshot to illustrate the problem.

So if some of you have already faced this problem and found the solution, tell me what you've done or at least what I have to do. 

(Sorry for my english if I have made mistakes, It is not my mother tongue)

Thanks.