Sync TrekMail Calendar and Contacts on iPhone and iPad

iOS supports CalDAV and CardDAV natively, which means you can sync your TrekMail calendar and contacts to your phone or tablet without installing anything. Events and contacts flow both ways: changes you make on your iPhone show up in TrekMail webmail, and vice versa.

Who this is for

You want your TrekMail calendar visible in the standard Calendar app on iOS, and your TrekMail contacts visible in Contacts, without going through iCloud or a third-party app. The setup also works on iPad.

The screens described below are from iOS 17. iOS 14 through iOS 16 use the same flow with very minor wording differences.

What you get

• Events you accept from email invitations in TrekMail webmail appear on your iPhone Calendar.
• Events you add on your iPhone show up in TrekMail webmail.
• Contacts edited on either side stay in sync.
• Notifications and reminders use iOS native settings, same as any other CalDAV calendar.

Settings you'll need

Use https://trekmail.net/dav/ for both CalDAV and CardDAV. If your White Label provider has explicitly supplied a verified branded DAV address, use that address instead. The Apps & devices screen currently lists email-client settings; it does not publish DAV addresses.

You'll enter the same three fields twice, once for Calendar, once for Contacts. iOS treats them as separate accounts.

App passwords only requires an app password for calendar and contacts sync; Mailbox password or app passwords accepts either. Create one in webmail under Settings > App passwords, or in the dashboard under Mailboxes > the mailbox > Security > App passwords. See Mail app passwords.

Setting up Calendar

1. Open Settings.
2. Tap Calendar → Accounts → Add Account.
3. Tap Other → Add CalDAV Account.
4. Fill in:
   • Server: use the DAV address from the table above
   • User Name: your TrekMail email
   • Password: an app password, or the mailbox password if the mailbox still accepts it
   • Description: anything you like, e.g. "TrekMail"
5. Tap Next, then Save when iOS confirms.

The Calendar app will discover your TrekMail calendars and start syncing within a minute or two.

Setting up Contacts

1. Open Settings.
2. Tap Contacts → Accounts → Add Account.
3. Tap Other → Add CardDAV Account.
4. Fill in the DAV address from the table above, your username, and password.
5. Tap Next, then Save.

Common problems

"Account verification failed." Check the mailbox's sign-in mode in Apps & devices. Use an app password if required, never your dashboard password. You may also see "Sign-in failed. This mailbox accepts app passwords only: create one in webmail under Settings > App passwords." Create one there and update the failing Calendar or Contacts account. A replaced or revoked app password needs to be updated too.

Events from TrekMail are missing. iOS Calendar respects per-calendar visibility. Open the Calendar app, tap Calendars at the bottom, and make sure your TrekMail calendar is checked.

Sync feels slow. iOS uses push for some account types and timed polling for CalDAV (typically every 15 minutes). For a manual refresh, pull down on the Calendar list.

Two-factor authentication. Mailbox 2FA protects webmail sign-in only. Calendar and contacts apps never ask for a code. Turning on 2FA in webmail offers Also require app passwords for mail apps, on by default; if selected, use an app password here. Webmail still uses the mailbox password plus a code.

Tip: sync only the calendar, not the contacts

If you already manage contacts elsewhere (Google, iCloud), you can skip the CardDAV step. Setting up only Calendar is fine; CalDAV and CardDAV are independent.