This device can’t use a Trusted Platform Module. Your administrator must select the "Allow BitLocker without a compatible TPM" option in the "Require additional authentication at startup" policy for OS volumes.
Go To Computer Configuration – Administrative Templates – Windows Components – BitLocker Drive Encryption – Operating System Drives
On the right-hand side, you will see an option called Require additional authentication at startup. Go ahead and double-click on that option.
By default, it is set to Not Configured, so you’ll have to click on the Enabled radio button. Automatically, it should check the Allow BitLocker without a compatible TPM box, but if not, make sure to check it.
Now go back and turn on the bitlocker on the system drive. You will have to reboot before the bitlocker starts.