macauth problem with specific device

hello all,
We are using 1.2.4 version of coova for a long time..We didnt have much problems so far.
But today i found out an interesting problem.

I was trying to add a mobile client to our macauth list.(kept on radius)
As usual, i added devices macid to radius with a password (which same password is in macauth parameter)
What happened is,
when user got connected to coova, radius sent an accept to coova for its macid/password as it does to all other clients in same situation.
With coova_query command i can see the device as status "pass", but in a second status turns into "none". And stays as it is.

Meanwhile other devices can login via macauth normally.

And for this device, if i remove it from macauth list, user can log on via webpage normally also.

Device is android 2.1.

I dont know what can effect but there are other android 2.1 devices working in same conditions.

So what causes the client to change status to "none" and what is that "none" i can understand pass, dnat but none??