That would explain it: as you can see in REP-3: Target Platforms - Platforms by Distribution - http://www.ros.org/reps/rep-0003.html#melodic-morenia-may-2018-may-2023, only amd64 (for x86 architectures) of Melodic is supported with packages on the ROS buildfarm.
That would explain it: as you can see in REP-3: Target Platforms - Platforms by Distribution - http://www.ros.org/reps/rep-0003.html#melodic-morenia-may-2018-may-2023Melodic Morenia (May 2018 - May 2023), only amd64 (for x86 architectures) of Melodic is supported with packages on the ROS buildfarm.