Phantoms don't spawn, even after 3 game days.

I was planning to create a phantom farm in my world for elytra repairment. I tested phantom spawning but even after 5 game days (I used time add command, + 1000000) not a single phantom would spawn.  This is really annoying because phantoms was only just fixed a few days ago.  

 

Note: This is an infinite world!

 

Note: I switch from creative to survival. Did it muck up my insomnia?

 

Edit 1: A few more game days passed, still no phantoms!

 

Edit 2: Thanks for your comments guys!

 

Edit 3: I switched from normal to peaceful and back. Still no Phantoms!

 

Edit 4: I see, it has nothing to do with mob cap