cant send short code sms's

[eg789123]

Hi all

I have a swift with an interesting issue

I am on stock ROM, no flashing yet, marshmallow android.

And for some reason I can't send SMS to short code numbers,

I can send normal SMS without any issues,
But if I try send to 35050 my phone crash and reboot my network.

Message still don't get sent,

Any advice?, using stock messaging app,