Either its OS version and Driver version related. Or maybe cable / device related.
But you didn't tell any details, so what answer do you expect ? ;-)
Which version of Apple OS, which card, which firmware on card, which version of drivers ?
Whats connected via MADI on which port in what order ? Model / Firmware ?
Did something change in your setup ?
On the Apple computer: OS upgrade or RME driver upgrade ?
On the MADI card: firmware upgrade ?
In the chain or setup of MADI devices ?
What type of cables (copper or fiber if there is a choice) ?
Did you try to replace a MADI cable ?
Can you narrow the error down by reducing the number of connected devices
AND using a different cable or different port on your MADI card.
Contact problem ? Can you check seatment of PCIe in the PCIe socket or also
try another PCIe slot in the Apple ?
BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14