Initially thought this was a DNS issue but I've been having real problem resolving a lot of .com domains. So I checked over 4G network and had no problems. Thought it was ISP but others on same connection not finding any issues. So what changed? 10.13.4 > 10.13.5 is what! So I am now immediately suspsicious it's related to this but I don't know how or why. Maybe a bug. Pages are timing out in safari. Taking 10/15 seconds to load if they do. Suddenly everything works again. Then it's gone again. Any tips appreciated. Thanks. --- Post Merged, Jun 19, 2018 --- Yep seems it's Safari (macOS) - Chrome is working fine when Safari "can't find server" I cleared Safari's caches but made no difference. Safari is behaving as if it's got intermittent connectivity.