Have you try to use userman instead usermanager in your url? I tried this and it's working on all web browsers.

Solved... I just change the tx-power on the client side (deliberant) from 30dBi to 25dBi and all works fine. I thinks it just the problem on client side. When I reach out the limit (31dBi) it gets unstable. Thanks for help.

I have an RB433 with R52 miniPCI and Grid Antenna. On client side, I have a deliberant (APC 2S-20). I've setup the client and get -64dBm of signal. But the problem is, sometimes (frequently) the log (RB433 side) tells me that the client was disconnected, and reassociating and the connected again. It...