Hi, Santosh. Did you try to change SIM card on your phone and the device was locked by AVG Anti Theft? If yes, to unlock your device, data connection needs to be turned ON (Either Wifi or mobile data) and your device should be displayed in anti-theft portal.
Note: When you update your AVG AntiVirus for Android to the version 6.x, your mobile device is automatically removed from AVG Mobilation https://www.avgmobilation.com/ and added to the my.avg.com portal. Follow the below steps to reset the password:
On the lock screen, you will have an option to reset pin. You can click on it, email account appears, you can enter the password of the respective email Id and your device will be unlocked. If this not works, you can follow the below steps from anti-theft portal.
1. Click on the following link http://my.avg.com 2. Login to anti-theft portal using the my account credentials 3. Select the device from the left panel you wish to reset the anti-theft pin. 4. New tabs will appear for your selected device from which tap on Settings. 5. Tap on Anti-Theft Tab. 6. Enter PIN confirm PIN again. 7. Tap on save to change PIN number for your device. Now you can use recent PIN to unlock the device.