I can't install fonts to my Note 4 since 5.1.1 update. This worked on KitKat 4.4.4 as well as Lollipop 5.1. Something is broken it think! I factory reset my phone after the latest androud security update that came out just a few weeks after the 5.1.1 update and this option still does not work.
I am experiencing the same problem, however I have found some monotype fonts that are compatible. The only thing is there 99 cents each and they are on the market