WARNING!!! Yahoo Mail is NOT secure!! If you are having issues with mail deleting on its own you may have someone ELSE viewing your emails!! I have someone's emails showing up on my ap. I have messaged said person from my email to get no response from them. I can see ALL their emails!! I can not even remove it as it's not in my "Add Contacts" section in settings on my phone. I'm currently looking into legal action and steps I need to take to ensure Google play knows this.