No repeat of message alerts.
I can not get message alerts to repeat. I have reviewed previous replies to similar posts and none of the proposed remedies suggested solve the problem. I get a single alert upon receiving a message, but regardless of how many repeat alerts I set in Notifications/Messages, I get only a single alert. I have closed Messages and restarted the phone several times after making Notification adjustments, but still receive only a single alert. Using iOS 11.2.6 on iPhone 8.