Print a test page without computer, using only internal test page from Epson. Should be full color if all is working correctly. If not, then the problem is in the printer. Might be a color tank problem or printing head problem. There are many models of Epson printers, there are many possible different causes of failures in the different hardware and internal software items of it. With no model number from you, no way to guess further.
If all colors are right, then the problem is with the computer. Since you tell nothing about it or its operating system, no suggestions about it from here.