Crest Audio Amps My Crest Audio X-eight Mixing Console Wont Let Me Use Solo Unless The Mute Is Off?

My crest audio x-eight mixing console wont let me use solo unless the mute is off? - crest audio amps

This is my audience and I think one of the recruit confused, but I do not know what they were doing. I can not for the MUTE mode, or have a lot of comments and consultation with the public what they should not. Can someone tell me how this could happen.