I can't mach build any more
Here's details of the issue i'm seeing

Downloading artifact to local cache: /Users/hubertbomamanilla/.mozbuild/package-frontend/a22e2cfeb6efdbc4-target.common.tests.tar.gz
 1:39.52 Error running mach:
 1:39.52     ['--log-no-times', 'artifact', 'install']
 1:39.52 The error occurred in code that was called by the mach command. This is either
 1:39.52 a bug in the called code itself or in the way that mach is calling it.
 1:39.52 You can invoke |./mach busted| to check if this issue is already on file. If it
 1:39.52 isn't, please use |./mach busted file artifact| to report it. If |./mach busted| is
 1:39.52 misbehaving, you can also inspect the dependencies of bug 1543241.
 1:39.52 If filing a bug, please include the full output of mach, including this error
 1:39.52 message.
 1:39.52 The details of the failure are as follows:
requests.exceptions.ConnectionError: HTTPSConnectionPool(host='firefoxci.taskcluster-artifacts.net', port=443): Max retries exceeded with url: /I-GfmgwsQsON9Omryn48Uw/0/public/build/target.common.tests.tar.gz (Caused by NewConnectionError('<urllib3.connection.HTTPSConnection object at 0x106dbbaf0>: Failed to establish a new connection: [Errno 60] Operation timed out'))
 1:39.52   File "/Users/hubertbomamanilla/Projects/mozilla-central/python/mozbuild/mozbuild/artifact_commands.py", line 188, in artifact_install
 1:39.52     return artifacts.install_from(source, distdir or command_context.distdir)
 1:39.52   File "/Users/hubertbomamanilla/Projects/mozilla-central/python/mozbuild/mozbuild/artifacts.py", line 1580, in install_from
 1:39.52     return self.install_from_recent(distdir)
 1:39.52   File "/Users/hubertbomamanilla/Projects/mozilla-central/python/mozbuild/mozbuild/artifacts.py", line 1476, in install_from_recent
 1:39.52     return self._install_from_hg_pushheads(hg_pushheads, distdir)
 1:39.52   File "/Users/hubertbomamanilla/Projects/mozilla-central/python/mozbuild/mozbuild/artifacts.py", line 1462, in _install_from_hg_pushheads
 1:39.52     if self.install_from_url(url, distdir):
 1:39.52   File "/Users/hubertbomamanilla/Projects/mozilla-central/python/mozbuild/mozbuild/artifacts.py", line 1435, in install_from_url
 1:39.52     filename = self._artifact_cache.fetch(url)
 1:39.52   File "/Users/hubertbomamanilla/Projects/mozilla-central/python/mozbuild/mozbuild/artifact_cache.py", line 218, in fetch
 1:39.52     dl.wait()
 1:39.52   File "/Users/hubertbomamanilla/Projects/mozilla-central/third_party/python/dlmanager/dlmanager/manager.py", line 101, in wait
 1:39.52     self.raise_if_error()
 1:39.52   File "/Users/hubertbomamanilla/Projects/mozilla-central/third_party/python/dlmanager/dlmanager/manager.py", line 116, in raise_if_error
 1:39.52     six.reraise(*self.__error)
 1:39.52   File "/Users/hubertbomamanilla/Projects/mozilla-central/third_party/python/six/six.py", line 696, in reraise
 1:39.52     raise value
 1:39.52   File "/Users/hubertbomamanilla/Projects/mozilla-central/third_party/python/dlmanager/dlmanager/manager.py", line 157, in _download
 1:39.53     with closing(session.get(url, stream=True)) as response:
 1:39.53   File "/Users/hubertbomamanilla/Projects/mozilla-central/third_party/python/requests/requests/sessions.py", line 555, in get
 1:39.53     return self.request('GET', url, **kwargs)
 1:39.53   File "/Users/hubertbomamanilla/Projects/mozilla-central/third_party/python/requests/requests/sessions.py", line 542, in request
 1:39.53     resp = self.send(prep, **send_kwargs)
 1:39.53   File "/Users/hubertbomamanilla/Projects/mozilla-central/third_party/python/requests/requests/sessions.py", line 677, in send
 1:39.53     history = [resp for resp in gen]
 1:39.53   File "/Users/hubertbomamanilla/Projects/mozilla-central/third_party/python/requests/requests/sessions.py", line 677, in <listcomp>
 1:39.53     history = [resp for resp in gen]
 1:39.53   File "/Users/hubertbomamanilla/Projects/mozilla-central/third_party/python/requests/requests/sessions.py", line 237, in resolve_redirects
 1:39.53     resp = self.send(
 1:39.53   File "/Users/hubertbomamanilla/Projects/mozilla-central/third_party/python/requests/requests/sessions.py", line 655, in send
 1:39.53     r = adapter.send(request, **kwargs)
 1:39.53   File "/Users/hubertbomamanilla/Projects/mozilla-central/third_party/python/requests/requests/adapters.py", line 516, in send
 1:39.53     raise ConnectionError(e, request=request)

Seem that you have network issues (or the server is down)

Yeah. my laptop connected to a wifi which seems to block that. tx