Returns 'failed' with 'cause' = 'exists' if the address is in use.
Returns 'failed' with 'cause' = 'invalid' if SIP address is malformed.
Returns 'failed' with 'cause' = 'exists' if the address is in use.
Returns 'failed' with 'cause' = 'invalid' if SIP address is malformed.
Returns 'ok' with an empty array if the search gave no results.
Returns 'ok' with an empty array if the database search fails.
Returns 'failed' with 'cause' = 'invalid' on invalid SIP addresses.
Returns 'ok' with an empty array if the search gave no results.
Returns 'ok' with an empty array if the database search fails.
Returns 'failed' with 'cause' = 'invalid' on invalid SIP addresses.