Hey there! I just updated to iOS 11 as well and have not seen this issue. What specific errors are you getting when trying to send these messages? Are you having issues sending iMessage (iPhone to iPhone) in general?
Hey there! Updates should improve things, not worsen them! Just wanted to check in and see if you were still having trouble with this. If so, we'd love to get a little more detail -- could you take a peek at the questions Chris asked above? Thanks!
Just want to know, is this still an issue? Please come back and let us know if you need help of if this was resolved. Thank you!