Hi there, welcome to the LUG.
From the sound of it, you have duplicates of the same channel strip in your project.
Concerning the red slash over the solo button, this is solo safe. The solo safe channel is usually assigned to track 256. If you imported an arrangement from an older version of logic, and perhaps increased the size of the mixer over time, there may be more than one channel strip set to solo safe. Ctrl click on the solo button to return it to normal, but remember that logic wants one channel strip to be set to solo safe in order to facilitate play back from the sample editor. It makes sense not to use this channel strip for any audio material in your arrangement. To illustrate how Logic likes this to be, simply create a new arrrangement, add, for the sake of argument, 24 audio tracks. Open the Audio environment and you should see two channel strips with solo safe on. One is set to audio 256, the other, which is intended to play the click track a.k.a klofpgeist, is set to instrument 256.
kind regards
Mark