print from iphone
1) Make sure your printer was powered on
2) Is ink low?
3) Is any error message of printers 
4) Try to print a test page  on your computer as follow steps
      Find “printer properties” >> general tab >> print a testing page
5) Uninstalling and re-installing your print drivers.

Double click on the home button of your iOS device. 
See if there is a Print Center, and then DELETE ALL print jobs inside.
If print jobs are backed-up on the Print Center it will  block off any new print job from printing.
Now, Try print it again