Maybe the command format is different. Check what you see in the logs with the documentation from your device vendor.
The command by cell phone is different, in the log it shows that the command was sent, without error. But the blocking does not happen.
It worked normally, I realized that after I made some changes to the traccar.xml file it started to not work. I don't know if it has anything to do with it.
My TK311 tracker is not blocking through the app or via the web, I check the server log and the command appears as sent, but it does not block or unblock the tracker. I can only perform the blocking through the sms command, sent by cell phone message. Does anyone know how to solve this problem?