"Not Supported" error while sending 'Altitude Change' command to PixHawk

Hi guys,

I am using a STM32F103RB Nucleo Board to communicate serially over UART to a PixHawk (Cube Black running on PX4) using MAVLink protocol. I have been using the following webpage for reference: https://mavlink.io/en/messages/common.html

I am able to Arm/Disarm (MAV_CMD_COMPONENT_ARM_DISARM - 400) the system using my method and the message status is being monitored on another UART terminal and QGroundControl. These commands receive the expected status “MAV_CMD_ACK_OK”.

However, when I try to set the Altitude (MAV_CMD_CONDITION_CHANGE_ALT - 113), the command acknowledgement I receive is “MAV_CMD_ACK_ERR_NOT_SUPPORTED”. Has anyone faced this (or a similar) issue?

Thanks in advance for your help!