"This email is not valid."
Where: Create your school screen, or inviting an instructor in Settings.
Why: the email entered isn't shaped like an address (for example name@example.com): the @ or the domain is missing, or it contains a space.
What to do: fix the address and try again.
Didn't find your answer?
Write to bonjour@martialnote.com from your account's address, saying which screen is involved and the message shown. Support is by email only, with no guaranteed response time. Never send information about your students.