If you are trying to connect an M-Audio Axiom Pro 49 to a modern Mac, you have likely run into a wall. Unlike many modern "plug-and-play" devices, the Axiom Pro series relies on specific software drivers to unlock its advanced features (such as HyperControl for automatic mapping with DAWs like Pro Tools, Logic, and Cubase).
technology for its advanced features, standard class-compliant drivers often do not suffice for full functionality (like transport controls or automatic mapping). 1. Driver & Compatibility Status maudio axiom pro 49 driver mac
On newer Macs where the driver won't install, you can still use the keyboard as a standard MIDI controller: Documentation, driver and software downloads - M-Audio M-Audio Axiom Pro 49 on Mac: The Definitive
Directlink for Reason 5.0.1 and Record 1.5.1 (Win 10 & MacOS 10.14) DirectLink for ProTools 8.0.1 and later (Win 10 & MacOS 10.14) M-Audio iMac won't recognize midi keyboard - Apple Community maudio axiom pro 49 driver mac