Problem “Please, enroll in the course before starting the lesson”

Hello,

I have opened an online academy following the steps of Sensei's course. I have already asked you enough questions.
There is a problem that does not happen to all students, only to some. When they go to a course, even having paid and being logged in, they get the following message:
"Please, enroll in the course before starting the lesson." If you click there, it will return you to the beginning and so on. Impossible to enter the courses. I have reviewed everything 100 times and I am already a bit desperate because some have been able to enter and others have not.

Let's see if you can help me.
Thanks,
MJ

————————————–

Hola,

He abierto una academia online siguiendo los pasos del curso de Sensei. Ya os he preguntado bastantes dudas.
Hay un problema que no le ocurre a todos los estudiantes, solo a algunos. Cuando van a un curso, aún habiendo pagado y estando logueados, les sale el siguiente mensaje:
“Por favor, matricúlate en el curso antes de empezar la lección.”, si pinchan ahí les remite al principio y así sucesivamente. Imposible entrar en los cursos. Lo he revisado todo 100 veces y ya estoy un poco desesperada porque algunos han podido entrar y otros no.

A ver si me podéis ayudar.
Gracias,
MJ

The page I need help with: [log in to see the link]