What's the right preposition to use with the verb "enroll"?

The dictionary says that one enrolls in a university, but today I heard a person saying

"The student enrolled at the school."

Is it right? Can I use both the prepositions "in" and "at"?

Solution 1:

I generally hear enrol at an institution, enrol in or on a programme or course, and if you are the mouthpiece of the institution, I hear enrol with us.

Here's Macmillan:

Enrol

VERB [INTRANSITIVE/TRANSITIVE] British English pronunciation: enrol /ɪnˈrəʊl/

if you enrol at a school or other institution, or if someone enrols you there, you put your name on the official list of its students or members

enrol at: Andrew cannot enrol at his local school because the class is full.

enrol someone in/on something: Isabelle enrolled her brother in a training programme for engineers.

Solution 2:

From Cambridge Dictionary Online :

Enroll at an institution

Enroll in/on/for a course/department

Enroll with someone