'ive noticed over the last 2 months my XR occassionally gives me a "sending failed" error when trying to send messages and had to restart the handset to be able to send again. I thought it was the mobile number format in my address book so I re-entered them all. Then a random amount iof days later the error was back! The thing is, I was replying to a conversation already exisited fine! So a restart, and away we went again. Last week I was talking to my son and asked why he wasn't replying to my iMessages to his 8+ - after further discussion, he was having the same issues!
Tonight, it happenned to me again
So from what I can gather,,,
1. Happening when sending to Android and iOS devices
2. Not isolated to existing contacts - happened tonight with a nerw number I entered manually
3. Both the XR and 8+ are NZ new running iOS13 on Vodafone