Can you follow these steps:

 1. Download the v1.2.20220720 release MRIcroGL_macOS.dmg

https://github.com/rordenlab/MRIcroGL/releases

 2. Open the dmg file and copy to your applications folder.

 3. Open this version of MRIcroGl from your applications folder.

 4. If this fails, open up the terminal (Applications/Utilities/terminal) and launch the software with the -r argument to reset the settings:

/Applications/MRIcroGL.app/Contents/MacOS/MRIcroGL -r