When you turn on the server, it performs a series of tests to check the operation of the server components and some optional devices in the server. This series of tests is called the power-on self-test, or POST.
If a power-on password is set, you must type the password and press Enter (when you are prompted), for POST to run.
If POST detects a problem, an error message is displayed. See UEFI (POST) error codes for more information.
If POST detects a problem, an error message is sent to the POST event log, see Event logs for more information.