Depending on when you updated Julia, this might be a red herring because the server was also updated recently, see Changes to PkgServers storage backend - #4 by fredrikekre for some more information.
It looks like you can not connect to https://storage.julialang.net. Perhaps you are behind a firewall and/or proxy of some sort that don’t allow it.
This is (almost) never a solution and you should never use this “tool” so lightly since you may have data in there that will be lost.