I'm using GRASS GIS Ver 7.2.2. When I enter command mode and type "g.extension r.hypso" I get the message:
Downloading precompiled GRASS Addons <r.hypso>... ERROR: Extension <r.hypso> not found
This happens with all of the extensions I've tried to download (attempts over a 123-hourday period). I re-installed GRASS with no luck.
Update: I got an indication that the GRASS Addons server is experiencing technical difficulties. (I'd been trying to access it for 12 hours now). Now simply seeking confirmation of that finding. I wasam able to query the server's directories and get a list its contents but not successfully add an Addon to GRASS GIS.