I have installed Plex on my Raspberry Pi 4 following this guide. But when I try to play a movie it says,
A required codec could not be found or failed to install.

Also, when I clicked ‘claim server’, it took me to a login page which I logged and still in the General settings, I see the option to clam server and its saying that the server is not secure.
Are these two problem relative?
Server Version#: 1.19.5.3112
Player Version# !Idon’t know, Plex Web 4.34.3