Yeah, precisely. As that website I linked says, if the email looks suspicious but is technically valid, ask them "Are you sure you didn't mean this?", but let

Yeah, precisely. As that website I linked says, if the email looks suspicious but is technically valid, ask them "Are you sure you didn't mean this?", but let them choose what they put in. However, if the address as given is definitely invalid, then you can reject it and explain why. You can offer suggestions here too if any seem reasonable.