Hi, thanks for your kind reply!
I managed to upload the file you asked, Setting VoLTE to "on" did not fix the issue.
In short: my RUT955 is receiving sms, doing what I ask (reboot, restore,...) but it does not send sms (when I ask via sms for its status, for example). If I ask the device to limit itself to 2G, it sends sms. If I want to send an sms via webGUI, it does NOT work.
Thanks for your support