Mellow thanks for the answer.
Device running on the latest firmware.
When I try to send SMS via WEBUI the screen looks like this (after a while):
The fields with the phone number and text of the message are cleared automatically after the appearance of the message TIMEOUT
Unfortunately, it is physically impossible to connect to the device. it is located elsewhere. While access to it is possible only through RMS
There is no information in the eventlog about an attempt to send SMS.
Perhaps there is something in troubleshot, but I do not know exactly where to look.