My WAP371 disconnects in 5GHz band

[admin]

Hi,

Recently I've bought the WAP371 access point (European version) and updated it with the firmware 1.0.0.10.
Unfortunately this device does not work properly in the frequency band of 5 GHz, in the frequency band of 2.4 GHz it seems to work fine.
The issue in the frequency band of 5 GHz is that it causes disconnections in both modes; N and AC. I can reproduce this issue relatively easily if I transfer huge files (5-6 GB) over the device, but the disconnections occur sporadically also at low load.
Originally I blamed the Intel's Wireless-AC 7260 wifi card or it's device drivers/firmware, but having observed the same issue using different hardware/software/firmware combinations - I tested with a few laptops with different wifi cards (three Intel's Wireless-AC 7260 cards and one Centrino Ultimate N- 6300 AGN) running under different operating systems (MS Windows 8.1 and 7 Pro, Linux Arch64  with Kernel 3.15 and 3.16) - I'm sure that my WAP371 is to blame for the disconnections.
My questions are:
1. Are there other owners of the WAP371 having the same problems?
2. Is this a known issue of Cisco's WAP371, generally,  or is it rather an issue of my device only?
3. Is there anything I could try out before I give my WAP371 back?

Thanks in advance for any idea! 

[toussaintd]

After changing the channel from 44 to 36 in 5GHz and channel 6 for 2.4GHz. I finally succeeded a 70GB file transfert (download) for the first time. After that I try a time machine backup of 22GB, but it fails ... It's a shame. Even disabling 2.4GHz doesn't help.

The support should really get concerned with those problems. It has been 4 days of configuration by trial-and-error to get this "almost" working.

[toussaintd]

I enabled client Qos and Qos association and it seems to be working for now.

[jmnich011]

I just purchased four WAP371 APs along with the recommended external power supplies (Cisco Small Business SB-PWR-12V2A-NA 12V 2A Power ).

The APs seem to work okay but I may have to change the 5Ghz network settings, per the information below.

My observation is that even with using the recommended external power supplies, the power indicator displays RED vice GREEN.  Any ideas?  I hate to think that using the recommended external power supplies are under powered.  If true, I will rethink using Cisco in the future.