My WP dashboard goes blank, is it a plugin conflict?

1st
My dashboard goes blank time to time. There are just reliable plugins installed, so I have no idea what it is.

2nd
I cant add category icons to my directory. My developer could (thats you can see on my site) but when I try to do the same, just in the same way (FontAwesome) its just not good for some reason. Is this issue related to the 1st one? (dashboard also goes blank when saving the updates)