DGS-1250-52X (hardware version A1, firmware 2.02.B011) blocks udp traffic on port 5246, so CAP only can found capsman using L2.
Upd.
Problem solved with d-link firmware 2.03.B006
DGS-1250-52X (hardware version A1, firmware 2.02.B011) blocks udp traffic on port 5246, so CAP only can found capsman using L2.
Upd.
Problem solved with d-link firmware 2.03.B006