Email sign up wont add me???

Ive been trying for weeks now to add my email so I can get the free stars and the animals that require email. Why wont it work???? Also cheaper stuff would make game better and more decorations and say cages for some animals .,,,, plz help me add my email and I will give 5 stars n plz more decorations. Thanks

Serena12/456 about Tap Zoo, v5.2.1