Tracks muted

I’ve created a project with tracks spanning 55 minutes. When I view the project track list and align tracks E2E, each track is the color “blue”. I must have hit a wrong key or option because all tracks but one are now “grey” and muted when I try to play them. Only one track is “blue” and not muted. How do I un-mute all the tracks? Thanks.

If the “Solo” button is pressed on the non-muted track, click the “Solo” button to “un-solo” it.