The "main" network and "guest" networks are two different networks. Devices on the "main" network will not communicate with other devices on the "guest" network, and vice versa. After all, the reason to have a guest network is to keep guests from seeing devices on your main network.
If you want the printer to be available for use on the "main" network, then you will need reset the printer back to its original default settings and then set it up again to connect to the "main" network, not the "guest" network. Unfortunately, when you do this, "guests" will not be able to print if they are on the guest network.
If you want folks to be able to print from both the "main" and "guest" networks, then you will need two printers, one for each network.