I’ve exported a basic All caps font, drawn in Illustrator; then scaled and exported in Glyphs. I can open it with Font Book. But it wont install or appear in the main window. How do I install it? 
There is probably something missing. Can’t say more without seeing the font file. Can you send with email?
Problem solved. I asked my friend to install it and it worked. I tried it once again on my restarted Mac and everything worked fine. Thank you! sorry for the trouble.