First of all, make sure SMS is supported by your ISP.
Secondly, make sure that the "port" is not used by the PPP out interface:
[admin@Blabla] > tool sms send modem phone-number="+xxxxx" message="message" channel=2
failure: port's channel is already in use
If you see that the port is already in use, you need to free it. Try disabling and enabling the PPP interface back but!! do not send any traffic yet. Make sure that the "modem" port under "System>Ports" is not "Used by" anything.
Then, enable GSM debugging to see which AT commands are sent:
https://help.mikrotik.com/docs/display/ ... -Debugging
When port is not used by anything, you can issue the command like:
[admin@Blabla] > tool sms send modem phone-number="+XXXXXXXX" message="message" channel=2
if you still have issues, we advise creating a support ticket in our system:
The sim slot itself indicates how the nanoSIM card should be installed:
"cut" corner to the right