2018-05-20T07:15:42Z INFO --- logging initialized ---
2018-05-20T07:15:42Z DDEBUG timer: config: 6 ms
2018-05-20T07:15:42Z DEBUG Loaded plugins: builddep, config-manager, copr, debug, debuginfo-install, download, generate_completion_cache, needs-restarting, playground, repoclosure, repograph, repomanage, reposync
2018-05-20T07:15:42Z DEBUG DNF version: 2.7.5
2018-05-20T07:15:42Z DDEBUG Command: dnf --installroot /var/lib/mock/756465-fedora-28-x86_64-1526800541.094169/root/ --releasever 28 --disableplugin=local --setopt=deltarpm=False install @buildsys-build 
2018-05-20T07:15:42Z DDEBUG Installroot: /var/lib/mock/756465-fedora-28-x86_64-1526800541.094169/root/
2018-05-20T07:15:42Z DDEBUG Releasever: 28
2018-05-20T07:15:42Z DEBUG cachedir: /var/lib/mock/756465-fedora-28-x86_64-1526800541.094169/root/var/cache/dnf
2018-05-20T07:15:42Z DDEBUG Base command: install
2018-05-20T07:15:42Z DDEBUG Extra commands: ['--installroot', '/var/lib/mock/756465-fedora-28-x86_64-1526800541.094169/root/', '--releasever', '28', '--disableplugin=local', '--setopt=deltarpm=False', 'install', '@buildsys-build']
2018-05-20T07:15:42Z DEBUG Unknown configuration option: best = 1 in /var/lib/mock/756465-fedora-28-x86_64-1526800541.094169/root/etc/dnf/dnf.conf
2018-05-20T07:15:42Z DDEBUG repo: downloading from remote: copr_base, _Handle: metalnk: None, mlist: None, urls ['https://copr-be.cloud.fedoraproject.org/results/wanzenbug/firefox-nightly/fedora-28-x86_64/'].
2018-05-20T07:15:42Z DEBUG not found deltainfo for: 'Copr repository'
2018-05-20T07:15:42Z DEBUG not found updateinfo for: 'Copr repository'
2018-05-20T07:15:42Z DEBUG copr_base: using metadata from Sat 19 May 2018 11:05:44 AM UTC.
2018-05-20T07:15:42Z DDEBUG repo: downloading from remote: fedora, _Handle: metalnk: https://mirrors.fedoraproject.org/metalink?repo=fedora-28&arch=x86_64, mlist: None, urls [].
2018-05-20T07:15:45Z DEBUG not found deltainfo for: fedora
2018-05-20T07:15:45Z DEBUG not found updateinfo for: fedora
2018-05-20T07:16:09Z DEBUG fedora: using metadata from Wed 25 Apr 2018 04:27:32 AM UTC.
2018-05-20T07:16:09Z DDEBUG repo: downloading from remote: updates, _Handle: metalnk: https://mirrors.fedoraproject.org/metalink?repo=updates-released-f28&arch=x86_64, mlist: None, urls [].
2018-05-20T07:16:09Z DEBUG Cannot download 'https://mirrors.fedoraproject.org/metalink?repo=updates-released-f28&arch=x86_64': Cannot prepare internal mirrorlist: Status code: 503 for https://mirrors.fedoraproject.org/metalink?repo=updates-released-f28&arch=x86_64.
2018-05-20T07:16:09Z DDEBUG Cleaning up.
2018-05-20T07:16:09Z SUBDEBUG 
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/dnf/repo.py", line 229, in _perform
    return super(_Handle, self).perform(result)
  File "/usr/lib64/python3.6/site-packages/librepo/__init__.py", line 1522, in perform
    _librepo.Handle.perform(self, result)
librepo.LibrepoException: (10, 'Cannot prepare internal mirrorlist: Status code: 503 for https://mirrors.fedoraproject.org/metalink?repo=updates-released-f28&arch=x86_64', 'Error HTTP/FTP status code')

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/dnf/repo.py", line 914, in load
    self._handle_load(handle)
  File "/usr/lib/python3.6/site-packages/dnf/repo.py", line 657, in _handle_load
    return self._handle_load_core(handle)
  File "/usr/lib/python3.6/site-packages/dnf/repo.py", line 670, in _handle_load_core
    result = handle._perform()
  File "/usr/lib/python3.6/site-packages/dnf/repo.py", line 233, in _perform
    raise _DetailedLibrepoError(exc, source)
dnf.repo._DetailedLibrepoError

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 64, in main
    return _main(base, args, cli_class, option_parser_class)
  File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 99, in _main
    return cli_run(cli, base)
  File "/usr/lib/python3.6/site-packages/dnf/cli/main.py", line 115, in cli_run
    cli.run()
  File "/usr/lib/python3.6/site-packages/dnf/cli/cli.py", line 1013, in run
    self._process_demands()
  File "/usr/lib/python3.6/site-packages/dnf/cli/cli.py", line 766, in _process_demands
    load_available_repos=self.demands.available_repos)
  File "/usr/lib/python3.6/site-packages/dnf/base.py", line 353, in fill_sack
    self._add_repo_to_sack(r)
  File "/usr/lib/python3.6/site-packages/dnf/base.py", line 118, in _add_repo_to_sack
    repo.load()
  File "/usr/lib/python3.6/site-packages/dnf/repo.py", line 926, in load
    raise dnf.exceptions.RepoError(msg)
dnf.exceptions.RepoError: Failed to synchronize cache for repo 'updates'
2018-05-20T07:16:09Z CRITICAL Error: Failed to synchronize cache for repo 'updates'