Microsoft is currently investigating ongoing issues with Microsoft 365 that are preventing some Exchange Online users from accessing their mailboxes. The company has identified an issue concerning Exchange Online connectivity for North American users and is investigating further. Thousands of users across the globe are reporting server connection and login issues, as well as difficulty accessing their Outlook mailboxes. Some customers are experiencing errors when trying to log into their accounts or are caught in a sign-in loop. Microsoft has stated that these issues only affect North American users. Last month, Exchange Online customers worldwide were blocked from accessing their mailboxes and sending or receiving emails. Microsoft has also recently addressed issues preventing some users from searching across multiple services, including Outlook on the Web, Exchange Online, SharePoint Online, Microsoft Teams, and Outlook desktop clients. Customers should monitor the Microsoft 365 admin center for updates on this ongoing issue.