The following parts will not be manufactured

Hi, I’ve been trying for several weeks to get an object composed of three parts, but I can’t get the three parts to come out correctly for manufacturing. Could someone tell me what I’m doing wrong to get everything right and get the G-Code?

I have placed the three parts with the same axis origin, separated the parts so that they do not touch each other, but it does not work.

Thank you very much for your help.