Launch DC-Unlocker client
Open Server tab, enter your username and password that you received after credits purchase. Click "Check login". (you can buy credits here www.dc-unlocker.com/buy). If DC-Unlocker/Vygis/Rocker/Infinity dongle is connected, only click " Check login ".
Insert SIM card that does not work with your device for correct lock status. Detect it by selecting ZTE modems from manufacturer's drop down menu list, then click magnifying glass button. Wait till program detects it.
Open Unlocking tab, click “Unlock” button, wait for device to be unlocked.
After you see that modem was successfully unlocked, restart it by disconnecting and connecting back. Now you can use it with any SIM card.
If you can't set new connection settings on original dashboard of the device (like adding new profile along with APN settings) then download this file, and replace it with existing one in directory of where dashboard of device was installed (Default directory of the file should be C:Program FilesAirtel 4G InternetUiFileConnection Settings.ui).
Note: if device is not detected by it's dashboard and is missing from network adapters check this procedure to fix it here