I am unable to populate a default value to a date/time question.

In my example I want to set the default value to the current date/time. Like now().

The "Date format" is populatet as: yyyy-mm-dd HH:MM

Tried many combinations as shown below:
Info taken from http://php.net/manual/de/function.date.php

The system creates the date / no time value will be set:

{date("dd.mm.yyyy HH:MM")} => 2020-02-02 00:00 (wrong date / no time)
{date("d.m.Y H:i")} => 2019-12-13 00:00 (wrong date / no time)
{date("Y-m-d H:i")} => 2013-02-20 00:00 (correct date / no time!)
{date("Y-m-d H:i:s")} => 2013-02-20 00:00 (correct date / no time!)
{time("Y-m-d H:i:s")} => 1999-11-30 00:00 (wrong date / no time)
{time("H:i")} => 1999-11-30 00:00 (wrong date / no time)