FS-3962 --resolve

src/mod/applications/mod_dptools/mod_dptools.c

@@ -3326,7 +3326,7 @@ static switch_call_cause_t user_outgoing_channel(switch_core_session_t *session,
 	if (var_event) {
 		switch_event_add_header_string(var_event, SWITCH_STACK_BOTTOM, "dialed_user", dialed_user);
 		switch_event_add_header_string(var_event, SWITCH_STACK_BOTTOM, "dialed_domain", domain);
-		if (!strstr(dest, "presence_id=")) {
+		if (!zstr(dest) && !strstr(dest, "presence_id=")) {
 			switch_event_add_header(var_event, SWITCH_STACK_BOTTOM, "presence_id", "%s@%s", dialed_user, domain);
 		}
 	}