To update your Outlook setting:
For Mac 2011/2016:
Go to the Tools, Accounts, replace username with your email address, click Advanced, change server to https://outlook.office365.com/EWS/Exchange.asmx
for Directory service server, delete whatever is there to leave it blank. now click OK. whenever there is popup after this, click the checkbox always remember, and Allow.
If any popup windows show up after this, click Always remember, and click Allow.