Hello keirSpur,
Thanks for using Apple Support Communities. If you haven't already, review the steps in the Related Article at the top of this page to make sure you've followed all steps to set up iCloud Keychain.
If the issue persists, restart both devices. Restarting is a simple step that can resolve many unexpected behaviors.
Restart your iPhone
Restart your iPad
Let us know the results. Does the issue occur when connected to a different network? Be sure to include specific error messages and any other troubleshooting steps that you may have tried.
Have a great day!