Automatically sending of SMS via Nokia 3310

I told you to create a new thread but anyways..
to synchronize you have to send 0x55 ('U') 256 times.

Uart configuration is: 115200 8-N-1

My Nokia phone will not send SMS to short 5-digit numbers. I continually receive the message in red saying "Not sent, tap to try again.". It doesn't matter how many times I tap, and try, the same failure message appears. Where in the settings can I overcome this?

Source: www.smsala.com