The design is the visual features of the COFFEE MACHINE shown in solid lines in the drawings, whether those features are of shape, configuration, ornament, or pattern, or are a combination of those features. Shading is used in the drawings to better illustrate the design. The portions of the article shown in stippled lines form no part of the claimed design.Drawings of the design are included.FIG. 1 is a perspective view of the design;FIG. 2 is a front view thereof;FIG. 3 is a rear view thereof;FIG. 4 is a right side view thereof;FIG. 5 is a left side view thereof;FIG. 6 is a top view thereof; andFIG. 7 is a bottom view thereof.