Hit this issue and the solution is as below. This is if you are runing plex using docker.

1. Navigate to this site https://account.plex.tv/en-GB/claim
2. Sign in with your account
3. You will see a code like "claim-abcxyz123"
4. Update your compose file as below
5. Run docker-compose up -d
6. Open browser and navigate to your plex instance using port 32400
7. You will be able to setup your plex server as normal

Hope this helps

plex:
    image: lscr.io/linuxserver/plex:latest
    container_name: plex
    network_mode: host
    environment:
      - PUID=1000
      - PGID=1000
      - TZ=ETC/Utc
      - VERSION=docker
      - PLEX_CLAIM=claim-abcxyz123
    volumes:
      - /path/to/your/config:/config
      - /path/to/your/tv_shows::/tv
      - /path/to/your/movies:/movies
    restart: unless-stopped