I’m having trouble with redirect after the link.

I have a site where you have several types of entries. From the administrator to the student. In the case of the lower levels, they can not enter WP-Admin, otherwise it gives error that is not allowed or something like that.
Well when the student, logs in to the platform, it is redirected to the main page, everything normal so far. But if he re-enters the login screen, even though he is logged in, he is redirected to WP-Admin and the error appears.
I would like to know how to change this, or change the redirection for everyone, in which case everyone entering the login screen would be diverted to the home page than to the administration page.
Remembering that my administrators do not even use the login, to enter the dashboard. Instead they go straight into wp-admin, so if you have some way to redirect all the logins to the main page, you’d be grateful.

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