Why doesn't Tesla Unread show number of Yahoo emails?

I have a Nexus 6P phone with Tesla Unread and Nova Settings. The number of GMails in my inbox appear, but not the number of Yahoo emails. Gmails are controlled with regular phone settings, I got Tesla Unread specifically to show the number of Yahoo emails I have. Can someone please tell me how to set it so the number of Yahoo emails in my inbox appear on the home screen? TIA.

Audrey