Is the zigbee radio still enabled and on the right channel in settings? Read of other users having issues when the hub gets hot as zigbee seems to be the first to turn itself off. I have my C5 turned upside down so it can breathe better. My C4s are mounted on the wall.
Mine is mounted on a wall as well. It's pretty cool where I have it. I had a zwave plus device that was hitting my hub pretty hard. I removed it tonight and ran a zwave repair. Then I noticed that all of my zigbee stuff was gone from the routing table and none of my sensors and bulbs were responding. I turned the hub off safely. I'll see how things are doing in 18 minutes when I turn the hub back on.
I’ve found that hitting a refresh on the zigbee device’s page will usually cause it to re-appear on the getChildAndRouteInfo page. Doesn’t work 100% though.
I watched it for about 10 minutes and refreshed several times. Nothing. So strange. I just turned my hub back on. I'll see what I end up with.
Ok .. maybe crisis averted. Everything is responding again. And actually responding very well. All because of a zwave device going rogue. Lesson learned.
how do you identfy that?
Also, could you specify what was wrong in your image, just for those of us who have no idea
Well, normally, I probably wouldn't have been able to identify a problem that quickly. It was an older device that I remembered having some trouble with when I was on smartthings. But, I thought I'd give it a try. That was the only device change I made in months, so I was keeping a particular eye on how things were running after adding it to my mesh. There is a LOT of logic when it's recommended not to do too much in one day. Too many changes at once will make it difficult to pinpoint a problem and cost you more time than if you add things or change things slowly and pay attention to how your mesh and system are responding. I was lucky enough to benefit from this recommendation. More so out of laziness. 
So I had only really made two changes in the past two weeks. One is the lightify integration, which has been stable enough thus far, even in alpha stage and the other was a zwave plus device last weekend. I know it sucks to wait, but I truly benefited from taking things slow and thinking them through this time. Powering down my hub for 30 minutes after I safely excluded the z-wave device straightened everything out. It's still in tip top shape this morning. I'll wait for a few days to make sure that I'm back on track before I rework any automations. I'm planning on adding two new switches in our bathroom remodel and I'm waiting with breathless anticipation to receive them.
[EDIT]
There was one thing that I noticed: I lost a rule. I had a rule that turned on and off some lights in a bedroom based on motion. Probably a rule manager rule. It was gone. Seriously ... just gone. So I threw it in simple lighting.
