When making external calls I was getting the below error before even ringing I was always getting 
	
	
		SIP 480 / Temporarily unavailable / No user response 
	
	
		The account you are trying to dial appears to be unavailable. 
	
	
		  
	
	
		Since then, I've found in the phone setup under Account settings there is an option for Australian international where I've put 61 
	
	
		  
	
	
		I can now call any other VOIP phone system we have using a 0 prefix (0 is selecting an available line on the system) ie: 
	
	
		I can reach a shop lets say I call 00738794047 (who are also on VOIP MLPS network) but I still cannot reach a shop not on, ie 00733908808 (just doesn't even try to call). But dialing external Mobile numbers and some other land lines are still giving me the 480 
	
	
		Any help would be great, i tried Zoiper support but not a premium/biz user