Hi pbarrantes,

I found the similar solved issue. Probably it could be helpful: https://support.mozilla.org/uk/questions/1078320

Hi,

   Unfortunately, in my case, I already lost my bookmarks cause I had to reinstall my OS on one of my devices. Of course, I reinstalled thinking that, after syncing, my bookmarks would be there.

  In this fresh install, I created a new bookmark and it is not shown in my Android device, even after pushing sync several times.

   Thanks for your response anyway.

Some of my bookmarks synced but not all of them. It was woefully incomplete and I have a lot of bookmarks.

Could there be a limit to how many bookmarks can be synced?

I didn't have many bookmarks and they still won't sync.

I use Firefox for Android, Windows and Linux and, to this day, I still get the same result in all of them.