I am running the following command to get my encrypted obb file for apk expansion.
jobb -d /home/manoj/Desktop/Test -o main.1.com.example.helloworld.obb -k \
In my case, it solved running again the program, with the same parameters and the same content at the directory that I wanted to pack.
./jobb -d /media/assets/ -o my-app-assets.obb -k my_pass -pn package-name -pv your-version