At least i could find the issue on my End, after the update the IP Adress of that Docker Container changed. i had to set the checkBox in TrusNas. I only found that out because i used The Plex “Browser App” (https://app.plex.tv/desktop) with open Developer Tools (F12)
other way to find the Ip Adress of the Server is to try enabling Remote-Access ? (Fernzugriff in german). that your Ip Adresse is visible. mine was 127.10.2.1 or something … not even close to my Local network ^^.
just Check this Option if someone has a same Issue. Sry that i cant help with a Windows Host,
