Unable to register modem with network

Legacy Legacy AirPrime modules
1

Hi,
I am using wismo HT-W2101 gsm modem. I cant send sms from this device. It seems that the modem is not gettiing registered to the network. Can anybody help me out please, its really urgent
here is what I hace tried

at+csq      
+CSQ: 16,0          

OK  
at+creg?
+CREG: 1,2

OK
at+creg=1
OK

+CREG: 2
2

Hiya

Do you use WISMO228 or WISMO218 module? Just get information for Sierra, the module sometimes can’t register network in L20 firmware.