Aircard 341u network registration (CREG) report denial although modem works ok.

Working with the Netgear 341u on "Sprint" LTE network. 

Problem I exprience is that although the modem seems to work with factory defaults (on NAT/IPT mode, Windows/Linux doesn't matter) , I'm issuing AT+CREG? and gets :

+CREG: 0,3

Which AFAIK stands for "3 - registration denied".

Here is some more AT commands output -

+COPS: 0,0,"Sprint Sprint",7

!GSTATUS:

Current Time:  2840             Temperature: 42

Bootup Time:   0                   Mode:        ONLINE

System mode:   LTE             PS state:    Attached

LTE band:      B26                 LTE bw:      5 MHz

LTE Rx chan:   8763             LTE Tx chan: 26763

EMM state:     Registered     Normal Service

RRC state:     RRC Connected

IMS reg state: No Srv

RSSI (dBm):    -73              Tx Power:    0

RSRP (dBm):    -95              TAC:         0F03 (3843)

RSRQ (dB):     -10              Cell ID:     01E05B1A (31480602)

SINR (dB):      1.4

Thanks.