Find and fix email delivery issues as an Office 365 for ...
https://docs.microsoft.com/en-us/exchange/troubleshoot/email-delivery/email-delivery-issues
Instructions: Sign in to Outlook on the web for business. Run Microsoft Support and Recovery Assistant to fix Outlook problems or account issues - 10 minutes. If a single user in your organization is having trouble receiving email, it could be due to a licensing issue, a profile problem, the wrong version of Outlook, or a mix of other issues.
DA: 61 PA: 36 MOZ Rank: 87