To my knowledge, no mechanism currently exists in the backend codebase that allow administrators to do that, but the code is open source so, for example, a university wanting to set up a member-only instance can implement an email restriction themselves.
To my knowledge, no mechanism currently exists in the backend codebase that allow administrators to do that, but the code is open source so, for example, a university wanting to set up a member-only instance can implement an email restriction themselves.