Text replacements not syncing any more between Yosemite and iOS 9

I had syncing of the text replacements (System Preferences>Keyboard>Text in Mac OS and Settings>General>Keyboard>Shortcuts on iOS) working just fine.

At some point, it stopped working; I cannot tell exact;y when it stopped working.

I've got about 30 text replacements on my MacBookPro, and occasionally I change them.

Does anyone know how to make the synchronization work again?

Thanks a lot in advance.

Best regards,

Gabriel.

PS:

MacBook Pro Retina with 10.10.5

iPhone 6S with iOS 9.0.2