The command openssl rand -hex 64 generates 64 bytes of random data. When converted to hexadecimal format, each byte is represented by two hexadecimal characters. Therefore, the output string will be 128 characters long in hexadecimal representation, corresponding to 64 bytes of data. To clarify:
You need to update the BASE_URL environment variable on Planka docker. Change it to the cloudflared domain name as it is. After this you cannot access to Planka by typing local ip address.