Why can I not add my Outlook account to my S5?

[Android Central Question]

I had noticed that I was able to receive and read emails and attachments but not able to reply, it kept saying it was trying to 'load previous messages'. I have two email account that I have added under the Exchange server settings: my personal Outlook and work Outlook, both have the same problem. I un-added my personal account and tried to re-add it but now it just gets stuck on 'Retrieving account information' or it says 'Authentication failed'. I have tried clearing the cache from the email app and tried manual set up where I change the server to outlook instead of hotmail but have run out of ideas. Any help please would be great.