Can't sync annotations between devices?

I am unable to get my kindle to "sync" although all my annotations show up on the computer, they don't show up on my iphone. I thought that once you updated bookmarks and so forth on one device, they all synced together but it's not working for me. What should I do?

Is one of them on the beta program? Right now the beta version is pointed to a beta version of the annotation service and it doesn't sync with the prod version.

I don't know...one is my kindle fire and the other is my iphone and computer. I don't know why I can't sync the things I do on the kindle with the iphone. Any ideas?