Messages won't sync to iCloud

I have all my text messages saved on my MacBook Air and I recently bought a storage plan and turned on iCloud for all my messages. Some of my old messages transferred over to my phone but a couple of years are completely missing from iCloud. They are still on my MacBook but just not in iCloud. How do I fix this? I have tried turning messages in iCloud on and off on both devices. Signing in and out of iCloud and restarting both devices.