Issue with Mesh Network on a AP 100X

Question

I am really hoping someone has ran into this. 
 Setup is an XG 115 and about 6 AP 55C APs. I installed a AP 100X and it works great. Then I added a mesh network with the AP 100X (we will call this one ROOT) as the root and then a second AP 100X (we will call this one MESH) as the mesh. No matter what I tried I couldn't get the MESH AP 100X to connect to the mesh network. I worked with Sophos support for 4 hours and they tried everything and couldn't get it working either. 
 We tried same channels, different names, etc... EVERYTHING!! They eventually told me they need to research it and will get back to me. 
 
 If I choose one of the AP55Cs as the root then the MESH AP 100X connects to it no problem so it seems to be only when the ROOT AP 100X is the root device. I need to get this working using the AP 100X as I am trying to span a gap of about 250 feet and the AP 55C isn't strong enough to make that especially since it is inside. 
 
 Anyone ever run into this before? 
 
 Thanks, 
 J

RolandD · Answer

Hey Joey, 
 Just had a similar issue setting up a bridge between two AP 100X's managed with an XG115w to connect two buildings. 
 When the AP 100X was the root device, the remote AP 100X would never come online. When searching I found your post and thought it was quite strange to see you with an almost identical problem. So I tried with a spare AP55 as the root device and the bridge came up without issue. 
 I had done a pattern update on the XG to AP Firmware 11.0.008, while this didn't seem to immediately solve the problem the bridge came up on its own while speaking with support about the issue - about 35 minutes after the last restart. I then power cycled everything for the bridge and it came up within 2 minutes. 
 I suspect one or the other AP possibly had not taken the new AP firmware and I simply was not waiting long enough for it to update. 
 I can confirm AP 100X as a mesh root device is working as expected, make sure your pattern updates are done and let the AP's sit for a while. 
 Good luck.