Here is the answer :
Hi, I have seen the same problem with my wifi card RT2790.
It's not a problem of wifi card but a bug between this kernel and hostapd.
It's corrected on the kernel 2.6.32-593 but I don't find this kernel for teh clearod/centos 6.7
So I have installed the kernel-lt 3.10.96 for elrepo and youpi it works.
You can see all the process (in french sorry) here :https://www.prestaopen.com/informatique-prestaopen/clearos-correction-maj.html
Regards
Gilbert

Hi I try to patch but without success
so you cansee the answers of this post :
https://www.clearos.com/clearfoundation/social/community/wireless-ap-broken-after-update
Regards
Gilbert Marin

The kernel from upstream with the wireless fixes is in the updates-testing repo and will go out to the community on next Tuesday unless there are any issues. I will be testing this against ClearBOX and other devices I have but would sure love some feedback before this goes to the community.

Thanks for the reply back. I ended up doing that, I upgraded my kernel with 3.13.2-1.clearos.x86_64 along w/ headers and devel and everything is working great. I downloaded this from http://download.clearfoundation.com/community/timb80/repo/clearos/6/testing/x86_64/.

thanks again

You can the answers of this post :
https://www.clearos.com/clearfoundation/social/community/wireless-ap-broken-after-update
Regards
Gilbert Marin