~/.../github.com/snapcore/snapd$ snap install hello-world
error: cannot install "hello-world": cannot get details for snap "hello-world" in channel "stable":
       got unexpected HTTP status code 503 via GET to
       "http://localhost:9999/snaps/details/hello-world?channel=stable&fields=anon_download_url%2Carchitecture%2Cchannel%2Cdownload_sha3_384%2Csummary%2Cdescription%2Cdeltas%2Cbinary_filesize%2Cdownload_url%2Cepoch%2Cicon_url%2Clast_updated%2Cpackage_name%2Cprices%2Cpublisher%2Cratings_average%2Crevision%2Cscreenshot_urls%2Csnap_id%2Csupport_url%2Ccontact%2Ctitle%2Ccontent%2Cversion%2Corigin%2Cdeveloper_id%2Cprivate%2Cconfinement%2Cchannel_maps_list"
~/.../github.com/snapcore/snapd$ snap install hello-world
error: cannot install "hello-world": cannot get details for snap "hello-world" in channel "stable":
       503 Service Unavailable
~/.../github.com/snapcore/snapd$ snap install hello-world
error: cannot install "hello-world": network trouble