Can you please try a special build where I've added a code to log error returned by GetAddrInfo? The try push is here: https://treeherder.mozilla.org/#/jobs?repo=try&revision=a9fbc1eae0ad3b6989fd2d2e42b449ae371f8ca0&selectedJob=225192845
Linux builds can be downloaded from: 32-bit - https://queue.taskcluster.net/v1/task/YQ59Q_ckRbqFDz7D4oCkrQ/runs/0/artifacts/public/build/target.tar.bz2 64-bit - https://queue.taskcluster.net/v1/task/L8QATV2TSkORJwzXFEI3vg/runs/0/artifacts/public/build/target.tar.bz2 The error is logged in GetAddrInfo module, so it has to be added to MOZ_LOG. Following MOZ_LOG is sufficient: timestamp,sync,GetAddrInfo:5,nsHostResolver:5 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1796979 Title: Intermittently can't connect to the server To manage notifications about this bug go to: https://bugs.launchpad.net/firefox/+bug/1796979/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs