Apple’s latest version of iOS, namely version 11, may struggle or flat-out fail to connect to Microsoft Office and Exchange mailboxes. That’s a rather annoying pain for anyone working in a typical Windows-based work environment.

The Cupertino idiot-tax operation admitted this week that iOS 11 contains a bug that potentially leaves users locked out of Microsoft Office 365, Outlook.com and Exchange inboxes, and that the mobile OS pops up an alert that reads “Cannot Send Mail. The message was rejected by the server.”

“If your email account is hosted by Microsoft on Outlook.com or Office 365, or an Exchange Server 2016 running on Windows Server 2016, you might see this error message when you try to send an email with iOS 11: ‘Cannot Send Mail. The message was rejected by the server’,” the owner of ClarisWorks claimed.

Source: Attention adults working in the real world: Do not upgrade to iOS 11 if you use Outlook, Exchange