Could you please try executing that commant apprending
sudo in the beggining of the command? Basically, the issue is that your standard azure user (The one you log in as) has no write permissions over
/opt/bitnami/apps/bitnami/banner/, so it can not create any new file there.
Cloud images (VMs) in general, require root permissions (append
sudo before commands) in order to operate with the application.
Let us know if this solved the issue.
We’ll be looking forward to receiving your reply.