Replaced Screen Display Not Booting Correctly

I am replacing a screen display on a client's iPhone 6. Replaced the screen fairly quickly, snapped it back together, and turned it on. Of course, it has to go through the black and white apple logo boot up screen for a minute or two, but it has been 10 minutes and it is still booting. I try a hard reset and it turns off, but then turns it self back on, shows a deep red screen for a second, and then right back to the black and white apple logo boot up screen. I am at a total loss and need some help. It has no water damage, new battery, new screen display from iFixit, and was only dropped from a foot or two. Any and all advise is welcome.