Snap behind a proxy

My distro is Manjaro XFCE and I am behind a company proxy with authentication.
I set-up snap following the guide in the install page for Manjaro [0]
For a series of reasons I set-up proxy configuration per-app or in case of consoles locally to a terminal via setting environment variables http_proxy etc. For bad / non-available proxy support I use proxychains [1].

Even when setting up correctly http_proxy, https_proxy variables in a terminal and then running e.g.

snap install skype

I get an error:

error: cannot install "skype": Get https://api.snapcraft.io/api/v1/snaps/details/skype?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%2Clicense%2Cbase%2Csupport_url%2Ccontact%2Ctitle%2Ccontent%2Cversion%2Corigin%2Cdeveloper_id%2Cprivate%2Cconfinement%2Cchannel_maps_list: proxyconnect tcp: dial tcp :0: getsockopt: connection refused

Tried with proxychains to no avail…

Any ideas or workarounds?

Thanks
Lorenzo.

[0] https://docs.snapcraft.io/core/install-manjaro
[1] https://github.com/haad/proxychains