Drobo runs a scaled down version of ARM linux, but directory structure is different from standard linux installs so that certbot can’t run on it. I am running a web server on my Drobo and it would be great if we could get certbot working and packaged as a droboApp.
acme.sh was a good idea, however it turns out, the dependencies are an issue - curl, openssl etc. Nothing that drobo does with their linux distro follows convention, so every package has to be tweaked to work in that environment. There are some good reasons drobo does this, but it gets annoying when you want to use it as anything other than just a NAS.