All of my Messages were sent. They all went through, were received, and I received replies to them. And, yes, I clicked on Resend Message. No fix. Someone responded, and I've also read this on web sites > "keep clicking on the "Ignore" button. Eventually the error message pop up will stop". Well, that seems like a sad situation for Apple, that there is no fix for this and just cross your fingers and it may go away some day.