Thanks for reaching out and welcome to the Community! That is very strange that some of your speakers are not working, I would be more than happy to help you out with this. We can go through some troubleshooting to try to get this resolved, I recommend checking that all the wires are connected properly and there are no debris blocking the connection.
If this does not solve the issue, then I recommend swapping the working cables with the speakers that are not working to establish whether it is the cable or the speaker that is not working.
I would like to know what system to have so that I can give you the most accurate information.