Many bots fails with the following error:

/usr/bin/python /b/build/slave/cache/cipd/goma/goma_ctl.py restart
creating crash dump dir (/tmp/goma_crash.chrome-bot).
Traceback (most recent call last):
  File "/b/build/slave/cache/cipd/goma/goma_ctl.py", line 2426, in <module>
    sys.exit(main())
  File "/b/build/slave/cache/cipd/goma/goma_ctl.py", line 2421, in main
    goma.Dispatch(sys.argv[1:])
  File "/b/build/slave/cache/cipd/goma/goma_ctl.py", line 1067, in Dispatch
    self._action_mappings.get(args[0], self._DefaultAction)()
  File "/b/build/slave/cache/cipd/goma/goma_ctl.py", line 839, in _RestartCompilerProxy
    self._StartCompilerProxy()
  File "/b/build/slave/cache/cipd/goma/goma_ctl.py", line 659, in _StartCompilerProxy
    self._GenericStartCompilerProxy(ensure=False)
  File "/b/build/slave/cache/cipd/goma/goma_ctl.py", line 600, in _GenericStartCompilerProxy
    latest_version, bad_version = self._GetLatestVersion()
  File "/b/build/slave/cache/cipd/goma/goma_ctl.py", line 694, in _GetLatestVersion
    raise ex
__main__.Error: Error(1): E0421 02:28:24.749608 11516 socket_pool.cc:453] connect to 2607:f8b0:4001:c06::64: Network is unreachable [101]
E0421 02:28:32.959223 11516 goma_fetch.cc:150] fetch https://clients5.google.com/cxx-compiler-service/downloadurl http code:0

See for example https://build.chromium.org/p/tryserver.chromium.linux/builders/linux_chromium_clobber_rel_ng/builds/162573/steps/compile%20%28with%20patch%29/logs/stdio.

This cause the CQ and try bots to fail.