Screen() Failure MacOS High Sierra

Hi all I am having some trouble with Psychtoolbox-3 on MacOS High Sierra, MATLAB 2020b. I am trying to run some code given by my lab coordinator for their research project, however, I can’t get anything to run because of the error pasted below.

I have tried redownloading PTB, or downloading other extensions suggested like gstreamer, but I am still getting the same error. I also tried following the Screen() Failure topic posted by Macos in bugs and features since it looked similar to my problem, however, the link given from the resolved solution did not allow me access to the thread. Even after registering an account on the website I was still denied access. I am not too sure what else I am missing, but any help would be greatly appreciated! (:

Invalid MEX-file ‘/Applications/Psychtoolbox/PsychBasic/Screen.mexmaci64’:
dlopen(/Applications/Psychtoolbox/PsychBasic/Screen.mexmaci64, 6): Symbol not found:
Referenced from: /Applications/Psychtoolbox/PsychBasic/Screen.mexmaci64
Expected in: /usr/lib/libSystem.B.dylib
in /Applications/Psychtoolbox/PsychBasic/Screen.mexmaci64

Error in ShowCursor (line 190)
Screen(‘ShowCursorHelper’, screenid, type, mouseid);

Error in sca (line 26)

Error in soundBlock (line 18)

UpdatePsychtoolbox to the latest (actually or later) may help.