We probably need more information.
First, this is for the Pro 1, not the Pro1x. Since this is your first post and you provide no information, just wanted to make sure you understood that, The instructions for the Pro1x is here:
Second, if you are asking about flashing Stock Android, I am left to assume you are on another OS such as Lineage. In which case, your bootloader is already unlocked as bad things happen if the bootloader is locked on another OS.