We’ve got 2 RUTX50 devices with the same problem, with the carriers Vodafone and Cosmote.
Per the thread SMS Failed to send message on RUTX50 I set the VoLTE option to On.
The terminal output was:
BusyBox v1.34.1 (2025-07-24 09:51:14 UTC) built-in shell (ash)
    ____        _    ___  ____
   |  _ \ _   _| |_ / _ \/ ___|
   | |_) | | | | __| | | \___ \
   |  _ <| |_| | |_| |_| |___) |
   |_| \_\\__,_|\__|\___/|____/
------------------------------------
     Teltonika RUTX series 2025
------------------------------------
   Device:     RUTX50
   Kernel:     6.6.92
   Firmware:   RUTX_R_00.07.16.3
   Build:      bae5a37252d
   Build date: 2025-07-24 11:11:38
------------------------------------
root@apothiki-2-rutos:~# gsmctl -S -s "+30REDACTED HI"
[gsmctl_send_sms:22] error: ERROR: Failed to parse response
I tried to register at the Helpdesk to open a ticket but couldn’t find a way.


