Cannot get dynamic IP address after resetting modem

Hi, I am using the EM7455 module on our custom Linux board. I got the EM7455 to work and I can use the udhcpc Linux command to acquire a dynamic IP address for the cellular interface. I use the /dev/ttyUSB2 serial port to issue AT commands to the module.

When I issue the AT+CFUN=1,1 command to reset the module, and then I wait for about 30 seconds for the module to register itself so that I see the /dev/ttyUSB devices, the module now responds to AT commands on /dev/ttyUSB0 serial port. When i issue udhcpc command to acquire a dynamic IP address, it does not get a new IP address. When I do AT+CGCONTRDP command, I see the IP address and the DNS server IP address that was acquired before the reset. Do I somehow need to clear these IP addresses?

Any clue why after doing a AT+CFUN=1,1 command, it no longer can get a dynamic IP address when I issue udhcpc command?