sms notification is not always working

I would appreciate it if someone could help me with the SMS problem, as it only functions from time to time. Mail and push working fine

here is my traccar.xml

What's the error when it's not working?

thank you for your help ,I am not receiving always SMS messages, i checked the logs, but I can't find anything with my limited knowledge.

I gave ClickSend a try, and the SMS notifications are always working now. The only strange thing I’ve noticed is that the phone number sending the SMS is different every time

it has a fixed number option also