Caddy's proxy stanza for defined path with spaces sometimes is working when
it's done like this:

  proxy /path with_spaces ip:port

It happens, that few first requests after starting Caddy it's working, but
then it fails with error message like:

  dial tcp: lookup with_spaces on ip: no such host

So to stabilise situation now paths are generated like:

  proxy "/path with_spaces" ip:port