The audio I/O of the Focusrite Scarlett Solo and the AKG Lyra may be recognized as two different devices with the Pro Tools on Mac. Aggregate them to be recognized as a set of devices on Mac and reset I/O on the Pro Tools to solve the issue.
Combine multiple audio interfaces by creating an Aggregate Device
https://support.apple.com/en-us/HT202000
Troubleshooting: How to set up multiple devices to be recognized as a set
https://support.focusrite.com/hc/en-gb/articles/115000166845-Second-Generation-Bus-Powered-Scarlett-Interfaces-and-macOS-Sierra-10-12-2
How to set up the I/O on the Pro Tools, How to reset the I/O
Pro Tools No Sound - How to reset I/O settings
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