ActiveSync on iOS Devices

Important after setup

Once you have enabled two-factor authentication, external applications such as Outlook, Thunderbird, DAVx⁵, or mobile calendar and contact apps can no longer access mailbox using your regular password.
To do so, you need to create an application password. Without enabled two-factor authentication (2FA), the use of application passwords is optional.

Set up Exchange ActiveSync on iOS devices

With Exchange ActiveSync (EAS), you can synchronize emails, calendars, contacts, tasks, and notes on your iPhone or iPad with your mailbox account. EAS is particularly convenient as it enables real-time synchronization ("push").

Note

EAS is a proprietary Microsoft protocol. While it generally works reliably on Apple devices, it does not support shared calendars or contacts. For maximum compatibility, we recommend using open standards such as IMAP, CalDAV, and CardDAV (see alternatives).

Requirements

• Active mailbox account
• iPhone or iPad running the latest iOS version

Option 1: Automatic setup via the mailbox web portal

1. Log in to mailbox from your desktop computer.
2. In the Connect your device widget, click the Connect button.
3. Select iPhone or iPad > Exchange ActiveSync.
4. On your iOS device, open the camera app and scan the QR code displayed on your desktop screen.
5. Tap the Safari notification that appears at the top of your camera view.
6. Approve the download and installation of the configuration profile.
7. Enter your mailbox password when prompted.

After successful installation, your device is configured for Exchange ActiveSync.

tip

If the setup fails or the device does not accept the profile, use the manual configuration method described below.

Option 2: Manual setup directly on the iOS device

1. On your iPhone or iPad, open the Settings.
2. Navigate to Mail > Accounts > Add account.
3. Select the account type Microsoft Exchange.
4. Enter the following access data:
   • Email: Your main mailbox address (e.g., firstname.lastname@mailbox.org)
   • Description: Any name you prefer (e.g., mailbox)
5. Tap Next.
6. If more information is required, enter the following:
   • Email address: You full mailbox address
   • User name: Part before the @ in your email address
   • Password: Your mailbox password
   • Domain: mailbox.org
   • Server: app.mailbox.org
7. Tap Next.
8. Choose which data to synchronize (e.g., Mail, Contacts, Calendar).
9. Confirm the synchronization.

Your account is now configured and synchronizes the selected data with mailbox via Exchange ActiveSync.

Adjust sync settings

Extend sync period for emails

By default, iOS only syncs emails from the past few days. To change the email synchronization period:

1. Open your mailbox account via Settings > Mail > Accounts.
2. Tap Sync Mail.
3. Select e.g., 1 Month.

For older emails, please access your mailbox using IMAP (see below).

Enable push notifications for subfolders

1. Navigate to Settings > Mail > Accounts > mailbox account > Fetch New Data.
2. Ensure that Push is enabled.
3. Adjust Fetch behavior for subfolders and set push as needed.

Limitations and alternatives

Limitation	Alternative
No support for shared calendars or contacts	Use CalDAV/CardDAV
Emails only sync up to 1 month	Use IMAP
Issues with large attachments (> 5 MB) may occur	Use IMAP or the webmailer

Alternative: Use IMAP, CalDAV & CardDAV

If you want more control or full support for all features, we recommend the following setup:

• IMAP for emails
• CalDAV for calendars
• CardDAV for contacts

These protocols are open, standardized, and fully supported on Apple devices.

For setup instructions, please refer to this article:

• CalDAV and CardDAV for Mac OS and iOS
• Setting up mailbox in the iOS mail App

Technical overview

Setting	Value
Server address	app.mailbox.org
Domain	mailbox.org
Username	Part before the @
Protocol	Exchange ActiveSync