You may need to install the adb-tools or android-tools depending on the operating system you are working on.
First Settings > About phone , and you tap quickly several times on the build number to activate the developer mode.
Then Settings > System > Developer options and you activate the USB debugging.
Connect the phone to the computer and acknowledge on Brax.
Open a terminal and give
adb devices
You should see the phone and “activated” or something similar.
Then give,
adb logcat | tee logfile
The logging information will both appear on the screen and be saved in a file called “logfile”
Then try to send and receive messages and after you finish hit CTRL+C to exit.
Send this file to Plamen so that we can check where is the problem exactly.