iOS 11 users who updated their iPhones and iPads this week have been given a nasty shock, upon discovering Microsoft email services will no longer function correctly.

Apple are reported to be ‘working closely’ with Microsoft to resolve the issues – affecting compatibility with Microsoft Exchange 2016, Office 365 and Outlook.com – which display an error message informing users that their mail account “Cannot send mail. The message was rejected by the server.”

One week on from Apple’s flagship iPhone X launch, the problem leaves the tech giant with a public relations headache, as early adopters of the newest touchscreen operating system rush to complain online.

Until this recent development, Office 365 had proved hugely popular with iPhone and Mac users – allowing them to plug Microsoft cloud infrastructure, for dull company email and calendars behind the scenes, into their favoured Apple devices and applications for a a more enjoyable user experience.

Rubbing salt in the wound, Microsoft also published an official support warning on Tuesday, rather mischievously entitled: “You can’t send or reply from Outlook.com, Office 365, or Exchange 2016 in iOS 11 Mail.app”. According to MacRumors, beta testers (including engineers at Lineal) were raising the Microsoft email service problem as early as July, although it appears to be unresolved by Apple’s developers.

Users urgently needing email are advised to download the Outlook for iOS app from the App Store as a lifesaving alternative, suffer a more Microsoft branded email experience, and await rescue from Apple bug fixers.