Mail not working after linking up with Iphone

It occurred around the time if not as a result of connecting my iPhone 6 with macbook 13" retina 2015. But the outlook mail account on mac has ceased to receive or send mail. It comes up with this message the following message,

"Only one mail account can be enabled at a time

Enabling the mail account jamesejspencer@outlook.com will disable jamesejspencer@outlook.com on this mac"