Did you place the OpenCat folder in the Arduino folder and removed the -mail so the folder is just named "OpenCat." This is normally what causes that type of error since the path isn't right to find the file.
I have dowloaded via Github the OpenCat-main.zip file. After that renamed the file to: OpenCar.zip. Then in the Arduino program this file added but then : Specified folder /zip file does not contain a valid library.
Rename the folder as OpenCat AFTER unzip.
removed the -main
Did you place the OpenCat folder in the Arduino folder and removed the -mail so the folder is just named "OpenCat." This is normally what causes that type of error since the path isn't right to find the file.