Troubleshooting & FAQ

Most issues come down to credentials or a sync-direction setting. Here are the common ones and how to fix them.

"Authentication failed" when connecting my CalDAV server

Almost always an app-password issue:

• If your server has two-factor authentication, your normal password won't work over CalDAV. Create an app password in your server's security settings and use that.
• Double-check the server URL is the base address (e.g. https://cloud.example.com) — you don't add the CalDAV path yourself.
• Make sure CalDAV is enabled for your account (required on Posteo, mailbox.org and Synology).

See Connecting your CalDAV server for per-server notes.

I enabled two-factor authentication on my CalDAV server and sync stopped

This is about 2FA on your CalDAV server (e.g. Nextcloud, Synology), not on your CalDAVconnect account. Once 2FA is enabled there, the server stops accepting your normal account password for CalDAV — you need an app password instead. If your connection still uses the old plain password, the CalDAV login fails and syncing pauses. Create an app password and update the connection's credentials. Your Google/Microsoft side is unaffected: it uses OAuth, not a password.

My CalDAV server uses SSO / SAML login

If you sign in to your CalDAV server via single sign-on — SAML or OIDC, common with company Nextcloud or logins backed by Google/Microsoft/Entra ID — you usually don't have a regular password that CalDAV clients can use. The fix is the same: create an app password (Nextcloud: Settings → Security → Devices & sessions) and use that in CalDAVconnect instead of your SSO login.

If you can't find the app-password option, your server administrator may need to enable app passwords / token-based access for CalDAV, since some SSO-only setups disable it by default.

My connection says it needs re-authorization

This happens when a Google/Microsoft token expires or you changed your provider password. Open the connection and click Reconnect — sign in again and syncing resumes immediately. Your pairs and settings are preserved.

An event didn't sync

Check, in order:

1. Sync direction — a one-way pair only propagates changes in that direction.
2. Connection status — a connection in an error or re-auth state pauses syncing until fixed.
3. Recurring event on a limited server — some servers don't support recurrence rules; those events are skipped by design (see How sync works).

If everything looks right, a full sync runs daily and will reconcile differences.

Recurring events are missing

A few CalDAV servers don't fully support recurrence rules. CalDAVconnect detects this and skips recurring events on those servers to avoid corrupting your calendar; single events continue to sync.

How do I disconnect or delete a connection?

Delete the connection from your dashboard. This stops syncing and removes the stored credentials. Events already synced to each side remain where they are — deleting a connection does not wipe your calendars.

Is my data secure?

Yes. CalDAV credentials and sensitive sync state are encrypted at rest (AES-256-GCM), and cloud access uses revocable OAuth tokens rather than stored passwords. CalDAVconnect is GDPR compliant.

Still stuck?

Need help? Contact support and we'll get you syncing.