I couldn't add Whatsapp in battery saving mode on my Windows Lumia 730 Windows 10 os, why?

[Windows Central Question]

i couldnt add whatsapp in battery saving mode in my windows lumia 730 windows 10 os

i am facing a problem while adding whatsapp in the battery saving mode. when i press the "+" to add an app the whatsapp in missing in the app list.
please kindly help me to solve this issue