Devices connected via WIFI are not able to find DLNA services outside the WIFI network

hi there,

my situation:

----> INTERNET ---> FRITZBOX ----> RBR40 (router mode) ----> WIFI DEVICES (my phone)

                                         |

                               DLNA  DEVICES

so at my FRITZBOX (network 192.168.178.X) i have several devices which provide DLNA services.

since i use the ORBI WIFI my mobile devices are no longer able to find these DLNA devices when scanning

the local network.

for example: if i start VLC on my mobile i can scan the local network. there i should find several devices which provide DLNA,

for example, SONOS, my NAS, MEDIA SERVER and so on.... but NONE of them were found since i use the ORBI.

is there any way to fix that ??????

thanks,

micha