FOTA using LwM2M BC660

Hi I am using BC660 module, I would like to perform FOTA using LwM2M. When I tried to test this with leshan server and a CoAP file server, i am getting error while downloading the file(error code 12). I could download the file from the CoAP server with other client applications. Problem while using BC660.
Following are my AT commands,

AT+QSCLK=0
AT+QLWCONFIG=0,leshan.eclipseprojects.io,5683,“IoTUST”,300,3
AT+QLWREG

Please provide your log information