First, ensure that you have a positive World Credit Balance. World Credits are required when making calls outside of our Free Calling Cities.
Second, ensure that you are dialling 011 + Country Code + Number. For example, if you want to call Buckingham Palace in London England, the number listed is "+44 303 123 7300" so you would dial 011443031237300 to make the call using Fongo.
Lastly, our wholesale provider blocks calls to certain countries (Iran, Nigeria, etc.), this is beyond our control, but we can get numbers whitelisted by request. If you are still having issues calling international numbers or require number whitelisting, please open a support ticket (link) and provide the number(s) which you are trying to call as well as the date/time of the call attempt(s).