Remote music transcoding only to 128 Kbit

[RayBan91]

Server Version#: 1.21.3.4021-5a0a3e4b2.x86_64
Player Version#: 8.1.2.18135

According to this topic: Android Plex app always transcodes all audio files, regardless I set 320Kbit transcoding music in setting page:

and when I’m playing music in home (LAN network) it is orginal (FLAC) quality:

…and this is fine, but when I’m out of my home network, using mobile (for example LTE network - Ping 18ms, ~7MB/s download and ~2MB/s upload) Plex always transcoding music to 128Kbit/s:

.

My home WAN network speed: 50dw / 5up MB/s… and even when I’m using (for example) directly streaming from my library (Subsonic API or VPN connection + NextCloud music add-on) there is no problem with network connection. But I don’t want …and I dont’t need use so much mobile transfer data.
In this case I’m using Samsung Galaxy S10e with all updates.

I’m wondering how can I set the music trancoding quality to 320Kbit/s (not 128Kbit/s) when I’m out of my home.

Regards!

[Super4Jet]

I think you are using an indirect connection, which means you don’t have port fowarding enabled and Plex serves as a proxy. And as bandwidth doesn’t grow on trees, Plex limits the traffic through their servers by telling your server to keep the bitrate low.

[RayBan91]

Whats you mean I don’t have port forwarding?

connection from Internet:

+
Server configuration:

and what you mean Plex server as a proxy? It’s single VM on Red Hat 8 with port forward on edge router.

[Super4Jet]

Oh you have that enabled? How strange… I don’t know then. I’m good at basic troubleshooting, but this is in the more advanced class.