MacBook showing padlock and password box - entered password but cannot log in

Apple does not participate on this forum. This is a user to user forum where we are just other regular users such as yourself volunteering our time & knowledge to assist people. This also means that instant replies are unlikely. If you wish to speak to an actual Apple agent, then you need to click the "Support" link and choose another option to call, chat, or email Apple directly. For this issue I don't know if it can be resolved online or whether a visit to a physical Apple Store or Apple Authorized Service Provider will be required.

The black screen with padlock icon asking for a password indicates a firmware password lock which is separate from your macOS login user account. If you don't know this firmware lock password, then you will need to provide Apple with acceptable proof of purchase along with an acceptable form or personal ID in order to have Apple or an Apple Authorized Service Provider to unlock the device. I highly recommend contacting the Apple Store or AASP prior to the appointment to make sure you have the proper paperwork.....Apple has a very strict policy on what Apple considers acceptable.

Here is an Apple article regarding the firmware password lock:

Set a firmware password on your Mac - Apple Support

FYI, Sometimes a Mac where the Activation Lock was removed can sometimes end up showing a firmware lock screen. I've personally seen this once or twice on the Intel based Macs where a PRAM Reset was able to remove the lingering aspect of the Activation Lock (Apple had provided that instruction to me).

If you do not know this firmware password and are not able to provide valid proof of purchase so Apple or an AASP can unlock the device for you, then this device will be a brick & unusable except to boot to the internal boot drive.

Please i just want speak to someone