In the new stable version of ROS (6.45.1), MikroTik has removed backward compatibility with the old API login method. When MikroTik implemented the new method (ROS 6.43), it announced that this would happen sooner or later. The new method works with passwords in plain text.
Read More…https://wiki5.ispadmin.eu/mikrotik-nefunkcni-api-v-ispadminu-4/?lang=en