Why does the wsnoistance error occur?

Question

Moodle

An error occurs

('Error calling Moodle API\n', {'exception': 'moodle_exception', 'errorcode': 'wsnoinstance', 'message': 'Manual enrollment method missing or disabled for course (id = {$a->courseid} )'})

What could be the problem? All kinds of rights were issued
by the debugger, it buzzes to the fullest, but I can’t figure it out.
Here’s the code I’m sending , you never
know