# Frequently asked questions

- [Sending e-mails from the platform doesn't work](/admin-guide/appendix/frequently_asked_questions/sending_e-mails_from_the_platform_doesnt_work.md)
- [How do I prevent teachers to subscribe or unsubscribe learners into/from their courses?](/admin-guide/appendix/frequently_asked_questions/how_do_i_prevent_teachers_to_subscribe_or_unsubscr.md)
- [How do I block access to the course catalog for learners?](/admin-guide/appendix/frequently_asked_questions/how_do_i_block_access_to_the_course_catalog_for_le.md)
- [How much bandwidth does the videoconference tool (admin/BigBlueButton) consume?](/admin-guide/appendix/frequently_asked_questions/how-much-bandwidth-does-the-videoconference-tool-admin-bigbluebutton-consume.md)