Mail app bugs - Microsoft account can not be added, tripled notifications with gmail

It is impossible for me to add Microsoft email account to the default email app. After authenticating on the authentication page, it tries to launch K-9 mail instead.
Also, I’m getting notifications for Gmail 2 or 3 times.

I have had same issue with Microsoft account actually. My temporary solution has been to forward emails to my e email. It worked when I had first gotten the phone but now it doesn’t.