When using a MacOS device along with a Solvo / Collabo, and connected to a display device such as a TV or projector the resolution is sometimes not shown correctly on the display device due to a mismatch in the communication data between the laptop and the screen. This is also called EDID data.
This results in the image not being shown in full screen on the display device or with black bars on the sides or at the top and bottom of the screen.
In some cases it might solve the issue, to set the resolution manually from the MacOS device in Display preferences. See the below video where it is explained how you can manually select between a list of resolutions, and you can select the one that offers the best fit for your laptop and display device.