Using the Telekom DNS addresses on the S-Series WAN-Port solved this error with inbound/outbound calls: SIP/2.0 403 Forbidden (R403_REQUEST_NOT_ALLOWED)
example: ring-group #10 has 15 members. one of them should ring after 10sec. all other members need to ring parallel. possible solution: adding a ring-group into a ring-group an use "sequential r...