You should never over lap channels that causes co-channel interference. If you have to then as stated above the AP's that are farthest physically apart should use the same channel.
Also, I would turn off 2.4GHz unless you NEED IT and even then you probably don't NEED IT on all 4 AP's. Try just on 2 AP's to reduce interference and see what happens. Many cases in our offices I have either completely turned off 2.4 or I have it on only 1 AP and absolutely no complaints about wifi since I did that.

@wrcombs said in Cant communicate:

@obsolesce said in Cant communicate:

@dafyre said in Cant communicate:

Glad you got it, but my money is on a b0rk3d windows update that broke it.

It's Windows XP... those don't get updates anymore.

the back office was Windows 7. . . . Isnt windows 7 still receiving security updates?

Yes, it's still widely deployed. But freaking ancient.

Also have you tested your ping to to NJ/NY data center for VULTR? Might surprise you.

I was surprised and ended up moving some things from Chicago to NJ/NY despite it being twice the distance from me as Chicago VULTR instances were (500 miles to Chicago, 1200 miles to NJ/NY). Latency went from 80/90ms to 30ms or less on average when I moved to NJ/NY Vultr instance.

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I is

Easier question to ask - did any computers loose power at all? If the answer is yes, then ask, was it all or just some? If some, then possibly you had a 3 phase power related issue. If not, then this is not an issue.

Hey, a new guy that I missed. Welcome.

@thanksaj said:

Not often, but my LAN connection goes from my dock to a switch through Powerline adapters to my other main 8-port switch and then to the router. If something fails at any number of points along that way, it's handy to have the failover.

Congrats on intentionally disabling a setting that is designed to make your system work better.