We understand the importance of ensuring your Message+ app is working the way it should Wendy2k. We are happy to help. What model phone are you using? Do you experience the same issue if you send the message through the native text messaging app on your phone? If you go to the Play Store on your device, does it show any available updates for the Message + app?
I am using a Samsung Galaxy S9+, running on Android 9 (Pie). Since I bought this phone from Verizon, Message+ is the native text messaging app on this phone. The Play Store shows that my app is up to date.