Samsung Smart TV & "Custom server access URLs"

Hi,

I have a "TV SAMSUNG UE48H6400 400Hz CMR Smart 3D" and a Plex Media Server installed to the Synology 716+ii

In Settings/Server/Network, if I set my server "https://mydomainname:32400" on "Custom server access URLs", all clients (Android, Web, Playstation) works from Local and Internet except the Samsung Plex App 2.006.

TV seen the server but application crashed on startup

If I disable ""Custom server access URLs", everything works like a charm but I cannot enable my VPN client.
Samsung Tv and Plex App are up to date.

Is it a way to solve this issue ?

I precise that I need of this option because when my VPN is enable, the public IP sent to the Plex.tv is not the good one.

Thanks,