First download Dc Unlocker from this link here
Get your ZTE ready for unlocking by removing the memory card if you have one in and insert an unsupported SIM card (not a sim from the network carrier)
Plug in the ZTE modem inside your computer allow the modem’s dashboard to come up then make sure to close it
Now unzip the file you have downloaded you can use winrar or winzip to extract it
Now open the file inside the folder named DC Crap.exe
on the first option select ZTE datacards, select auto detect and click search (see the picture below) it should detect your modem now
Now on the right hand side click unlocking and click unlock
within few seconds your modem should be unlocked and you will get a notification that your modem has been unlocked successfully