We usually call from S100 by directly typing the number, nothing needed in front. Now we are in a situation when we need to call a short 4 digits number (external) that has no prefix and it's in the range of internal users extensions and it fails. I have tried to add the number in contacts but still doesn't work. I have tried to put 0 in front of it also.
Where do I need to look in the settings or how can we bypass to call that external short number?