Based on the given constraints, the following email address fulfills all 3:
donkey@az.a-a
as it ends with domain label "a-a" which is more than 2 characters,
has each label "az" and "a-a" start with alphanumeric characters,
has each label "az" and "a-a" consist of alphanumeric characters separated only by hyphens if any.
Yet it is rejected by the program. Seems to be an unhandled edge case, probably quite rare but might prevent a person with such an email from being entered into the app completely.
Based on the given constraints, the following email address fulfills all 3: donkey@az.a-a
as it ends with domain label "a-a" which is more than 2 characters, has each label "az" and "a-a" start with alphanumeric characters, has each label "az" and "a-a" consist of alphanumeric characters separated only by hyphens if any.
Yet it is rejected by the program. Seems to be an unhandled edge case, probably quite rare but might prevent a person with such an email from being entered into the app completely.