Error msg: File exists, but it doesn't look like the Plex database

[UnitedGaucho]

Having this issue on Windows 11 and Ubuntu 24.04.
On startup, once the web UI opens, the field for Database File is red. When entering the database file location, the field stays red and hovering over the field prints the message "File exists, but it doesn't look like the Plex database"

Manually entering the location in config.json and attempting to start MEP results in the web UI not loading.
The db file is in the default location for both the Linux and Windwos PCs. On the Linux PC, the owner is user plex. Sunning MEP as sudo does not change anything. I also tried running the docker as it seemed to fix the issue for a reddit user here, but I get the error message: "...error while creating mount source path /var/lib/plexmediaserver/Library/Application Server/Plex Media Server': mkdir /var/lib/plexmediaserver: read-only file system"

So what am I doing wroing?

[danrahn]

Do you know if you have any items in your server that have markers already? At least one intro, credits, or commercial marker needs to already exist, as that adds a value to the database that this application relies on.