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How are the 4 LED matrices wired ?
Where did you get the code from ?
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So all of the pins are common to all of the displays and there is no separate pin on each of them ?
Please provide a link to where you bought them
You need to set the correct hardware. Read the MD_MAX72xx library documentation and change this to your hardware type.
#define HARDWARE_TYPE MD_MAX72XX::FC16_HW
If you don't know which one, try each in turn. Make sure you put the DATA IN on the right hand side of the display.