Validate the allowed domain for scheduling#4866

Sometimes it’s necessary to tell users which domains are allowed for scheduling. For example, in an educational institution, parents might be asked to use their institutional email for scheduling, but they don’t, and it needs to be made mandatory. Or perhaps Hotmail accounts have stricter spam filters, and it’s better to tell users to use Gmail for scheduling.

In either case, it would be helpful to have a feature that allows users to enable and disable this option and add the allowed domain for scheduling.

Thank you