Microsoft have changed something, and here’s how to fix it.
Traditionally, Microsoft have used a system called “Basic Authentication” to allow you to configure their mailboxes on systems such as Apple’s iOS Mail app. However, they are now rolling out a change to “Modern Authentication” and it’s prompting many people to have to re-configure their device in order to carry on using their mailbox in the iOS Mail app.
Symptom: You will be prompted repeatedly for the password for your Microsoft Office 365 account. Even though you enter it, the prompt keeps coming back and your iOS Mail app doesn’t update.
Cause: Microsoft has disabled Basic Authentication in Office 365.
Note: While it is possible to fix the iOS Mail app, we are now recommending that users may find the Microsoft Outlook app for iOS to be more useful. It allows you to access shared mailboxes, which the iOS Mail app no longer supports. If you’re making changes, now might be the time to switch to a more business-focused app. You can download the app for free from the Apple App Store.
How to fix the repeated iOS Mail password prompt
The key to fixing this is to enter the password in the right screen – not from the popup that keeps appearing on your device.
Firstly, open the Settings app on your iPhone or iPad.
Find and tap MAIL

Tap “Accounts”

Tap your mailbox from the list

Tap the blue link entitled “Re-enter Password”

Once you’ve re-entered your password, the blue “Re-enter password” link will most likely disappear and your iOS Mail app should continue to support your Microsoft 365 or Office 365 mailbox.
Switch to your usual Mail app and check to see that new mail is now arriving.
If you have any further difficulties with this, please call or email us as usual and we will be happy to assist you.