I have the S6 Edge Plus, I have downloaded over 200 Fonts from websites after this Marshmallow update I was told from Samsung & T-Mobile that Samsung has taken away our customization w/this new update. Thats why no fonts are working EXCEPT for the stock fonts that came w/the phone. Its driving me crazy as well I bought all these Font apps on the PlayStore, I even researched how to override the permissions. But the only thing we can do is wait 4 Samsung 2 reissue back our permissions. A rep from Samsung said most likely the next update will fix this issue. We are just gonna have 2 wait until the new update & see of they fixed it. I even told them if this's a permanent thing their profits will PLUMMET due to their HYPOCRIACY & Lies. Android is popular 4 the ability of personalization. Apple isn't, but if its permanent then alot of ppl will DROP THEIR ASSES & APPLE WILL GET THEIR BUSINESS
Ive even tried downloading the fonts on the PC & Laptop then extracting them then installed the font on the phone. NOTHING'S working. Its like they blackballed us from even doing that. I can use the fonts on my homescreen & text messages but NOT 4 USE on the Keyboard.