Interruption of Sending Notifications through traccar sms gateway

Hello everyone, I am having a problem with sending notifications from my traccar servers by SMS, it happens that for some reason the messages are not sent and remain in a queue being sent long after they were generated, I am using a sim with unlimited messages And I would like to know if this problem lies in the application or has to do with something external to Traccar, any clarification I would be very grateful for.

P.S
Sorry for my bad English

Impossible to tell without any technical info.

I am using the traccar sms gateway application, this is my configuration in the traccar.xml

<entry key='notificator.types'>web,mail,sms</entry>
<entry key='notificator.sms.manager.class'>org.traccar.sms.HttpSmsClient</entry>
<entry key='sms.http.url'>https://www.traccar.org/sms/</entry>
<entry key='sms.http.authorization'>[TOKEN]</entry>
<entry key='sms.http.template'>
        {
            "to": "{phone}",
            "message": "{message}"
        }
</entry>

In summary, what happens is that the application gives me a message cannot be sent error 1 and the sending of SMS stops and after I estimate about 12 hours the late SMS are sent.

Have you checked the app status?

The application is functional and with the corresponding permissions