Do you mean dailing a phonenumber with 13 digits? If yes, check your Number plan under Telephony / Sites.
If phonenumber has 10+ digits and no country code the number can't be dailed. You must change the number plan / add a new numberplan for 10+ digits phone numbers with the country.
"The Intra-Country match type can be used to classify national numbers within the site's own country. It matches numbers that start with the site's country code or has a total length of between 7 and 10 digits."