A valid email address is required
Report abuse returned reportAbuse.emailRequired (A valid email address is required.) when email is empty or invalid.
Why this happens
Client/server validation on the abuse form. Related: Enter a valid email address on other account flows.
Diagnose and fix
1. Enter a real mailbox address (with @ and domain).
2. Complete reason/body fields as required.
3. Complete captcha if shown (Captcha on report abuse).
4. See Report abuse (member).