---
title: "Resolving Sync Errors"
description: "Calendar synchronization issues happen when your connected calendar accounts lose authorization, experience permission errors, or become disconnected from your account. When this occurs, you may no..."
last_updated: "2026-10-15T19:19:43.842776+00:00"
canonical_url: "https://docs.calendar0.app/guide/troubleshooting/resolving-sync-errors"
---

## Overview

Calendar synchronization issues happen when your connected calendar accounts lose authorization, experience permission errors, or become disconnected from your account. When this occurs, you may notice that new events fail to appear on your calendar, updates made elsewhere do not show up, or your scheduling availability becomes inaccurate. 

The software continuously monitors the health of your connected accounts. When a connection issue is detected—such as a revoked password, expired permissions, or a disconnected account—you will see clear alert notices in your dashboard and sidebar pointing you directly to the fix.

```mermaid
flowchart TD
    A[Events missing or not updating] --> B{Account Health Check}
    B -->|All Good| C[Check Calendar Selections / Visibility]
    B -->|Needs Reconnecting| D[Reconnect Account]
    D --> E[Re-authorize Permissions]
    E --> F[Sync Restored]
```

## Understanding Sync Errors and Connection Issues

Connection and sync problems generally fall into a few clear categories depending on how the account communicates with your calendar provider.

| Error Type | What It Means | How It Appears in the App |
| :--- | :--- | :--- |
| **Revoked Grant** | Your password was changed, or calendar access permission was explicitly withdrawn at the provider level. | Warning badge on the account; banner prompting you to reconnect. |
| **Missing Scope** | Calendar read/write permissions were unticked during sign-in, leaving an account that cannot read any events. | Account loads with zero calendars or triggers a reconnection requirement. |
| **Deleted Resource** | A calendar was deleted or unshared directly within your provider account while still selected in your settings. | The specific calendar is skipped automatically while sibling calendars continue syncing normally. |

Supported calendar providers: `google`, `microsoft`, `apple`.

> [!NOTE]
> For Apple calendar accounts, synchronization relies on app-specific passwords. If you rotate or change your main iCloud password, your app-specific password becomes invalid and must be updated.

## Fixing Disconnected Accounts and Permission Errors

### Reconnecting Your Account

When an account requires attention, a warning banner will appear at the top of your dashboard, and a warning indicator will appear next to the affected email address in your sidebar and settings.

1. Navigate to your dashboard or go to **Settings** and select **Accounts**.
2. Locate the calendar account showing a connection warning or status error.
3. Click the **Reconnect** button next to the account email address.
4. For Google and Microsoft accounts, a secure pop-up window will open. Sign in and ensure all requested calendar permissions are allowed.
5. For Apple accounts, a credentials dialog will prompt you to enter your valid app-specific password.

> [!IMPORTANT]
> If your browser blocks the sign-in pop-up window during reconnection, allow pop-ups for this site in your browser settings and try clicking **Reconnect** again.

### Handling Deleted or Unshared Calendars

If you remove or unsubscribe from a calendar directly inside your Google, Microsoft, or Apple provider account, the system handles it safely:

- The software automatically skips missing calendars during background refresh cycles.
- Your remaining active calendars will continue to sync normally without interrupting your overall schedule.
- If you accidentally deleted a calendar you still need, restore it directly within your calendar provider, then return to your settings to refresh your calendar list.

> [!TIP]
> If events are missing from only *one* specific calendar rather than the entire account, check your sidebar view settings or **Conflict Calendars** settings to ensure the calendar hasn't been accidentally unticked or excluded from availability checks.

## Related

- [Connecting Calendar Accounts](https://docs.calendar0.app/guide/integrations/connecting-calendar-accounts)
- [Managing Calendar Events](https://docs.calendar0.app/guide/core-features/managing-calendar-events)


## Sitemap

See the full [sitemap](https://docs.calendar0.app/llms.txt) for all pages in this wiki.