If some error prevents the proper execution of an API, the system will return a fault string. What follows are some of the more common strings.
Invalid username or password included in a get_sms_messages method:
A get_sms_conversation method requested by user who is not the owner of this line:
(Applies equally to get_sms_conversations method.)
A get_sms_lines request accompanied by an invalid username or password:
A get_sms_lines request made when no lines are available ("blank" response):
A do_hangup_call method against a call that does not exist: