The iPad suddenly stopped sending emails. Any ideas?

Q: Q: The iPad suddenly stops sending emails, ensuing within the error “Sender’s deal with is invalid”. After investigating this error on-line, I discovered that some websites had been instructed to do the next on the system:[設定],[パスワードとアカウント],[メール],[送信メールサーバー]Move within the order...

My iPad has suddenly stopped sending emails. Any ideas?

Q: My iPad has suddenly stopped sending emails, and I've been getting the next error in consequence: "Sender's handle just isn't legitimate." In researching this error on-line, I noticed that a number of websites inform you to do the next on...