Microsoft To Do cannot connect: fix sync and login problems

If Microsoft To Do cannot connect, the usual causes are a Microsoft account problem, a stale app session, a network restriction, or a Microsoft service outage. The safest fixes are to check Microsoft service status, confirm you’re signed into the right account, and try another network before you do anything more disruptive. If only one device is affected, the problem is usually local to that device; if nothing connects anywhere, focus on the account, service status, or network.

What the error usually looks like

The problem usually shows up as endless syncing, lists that stay blank, tasks that never appear on one device, or a sign-in loop that keeps sending you back to the login screen. Sometimes you’ll see a message that Microsoft To Do cannot connect, and sometimes the app just spins without finishing.

A typical symptom looks like this:

Microsoft To Do cannot connect

You may also notice that changes you make on one device never show up elsewhere. For example, you add a task on your phone, but the same list on Windows stays unchanged. In that case, the app is still open, but sync is not completing.

Where this problem applies and where it doesn't

This can affect Microsoft To Do on Windows, iPhone, Android, and the web. It also affects the same Microsoft account across devices, so one bad sign-in or a service outage can make every device fail at once.

Before you start, keep these points in mind:

• You do not need administrator access for the first checks.
• You only need admin rights if you later clear protected app data, change firewall rules, or adjust corporate device settings.
• A restart is safe and often helps, but it should not delete your lists.
• If your tasks are not fully synced yet, avoid making a lot of edits on multiple devices until the connection is stable.

Use this rule of thumb: if nothing connects anywhere, suspect the account, Microsoft service status, or the network. If only one device fails, suspect the app install, cache, date and time, or a device-specific restriction.

The quickest fixes that solve most cases

Start with the least disruptive fixes. In most cases, the problem clears before you get to anything more involved.

1. Check Microsoft service status.

Look for a Microsoft 365 or To Do service issue before changing anything on your device. If there is an outage, the safest move is to wait until the service recovers.

If To Do is down for everyone, no local fix will hold until Microsoft restores the service.

2. Confirm you are signed into the right Microsoft account.

Make sure the account in To Do is the same one that holds your lists. A personal Microsoft account and a work or school account can look similar, but they do not always hold the same data.

If you are on the web, check the account shown in the profile area. On mobile, open the app’s settings and confirm the signed-in address. On Windows, check the account attached to the app profile.

If the wrong account is signed in, switch to the account that actually contains your lists. If the right account is already signed in and the app still cannot connect, move to the network check.

3. Try a different network.

Switch from Wi-Fi to mobile data, or from mobile data to another Wi-Fi network. If To Do starts syncing on a different network, the original one may be blocking Microsoft services.

On Windows, this is especially useful if you are on a work, school, or guest network. On iPhone and Android, a mobile data test is a quick way to separate app trouble from network trouble.

4. Restart the app.

Close Microsoft To Do completely, then open it again. On Windows, make sure it is not just minimized. On iPhone or Android, fully dismiss the app from the recent apps list and relaunch it.

If the app reconnects after a restart, the session was probably stuck. If it still spins or signs you out again, the session is likely stale and needs a fresh login.

5. Sign out and sign back in.

This refreshes the session and often fixes stale authentication tokens.

On the web, sign out of your Microsoft account, then sign back in. On Windows or mobile, do the same from the app’s account or settings area.

If the app connects after this, your issue was probably a stale login session or a temporary network problem. If it still fails everywhere, move on to the device-specific checks below.

If one device works but another won't

If Microsoft To Do works on one device but not another, the account is usually fine. That means you should focus on the bad device, not the whole service.

Start with the simple fixes first:

1. Check the date and time.

An incorrect clock can break sign-in and syncing because the app cannot validate secure connections properly.

On Windows, open Date & time settings and turn on automatic time. On iPhone or Android, set the device to automatic date and time.

Windows: Settings > Time & language > Date & time
iPhone: Settings > General > Date & Time
Android: Settings > System > Date & time

If the clock was wrong, fix it and try syncing again. If the clock was already correct, the device probably has a different local problem.

2. Update the app.

An older app build can get stuck with a session problem or sync bug. Update Microsoft To Do from the Microsoft Store on Windows, the App Store on iPhone, or Google Play on Android.

If the web version works but the app does not, updating the app is still worth doing first. If you are already current, move on.

3. Clear the app cache or repair the app on the affected device.

This is often enough on Android. On iPhone, the usual equivalent is removing and reinstalling the app if the problem persists. On Windows, you can use the app’s reset or repair options from system settings.

Windows: Settings > Apps > Installed apps > Microsoft To Do > Advanced options
Android: Settings > Apps > To Do > Storage & cache

If the system offers a cache clear or repair option, use that first. It is less disruptive than a full reinstall.

If clearing cache or using repair fixes the device, the app had a broken local state. If it does not, the device may still be holding a bad session or blocked network setting.

4. Reinstall only on the affected device if nothing else helps.

Reinstalling the app is usually safe for cloud-synced lists, but do not do this as your first step if you still have unsynced changes on that device.

Reinstalling can clear a broken local state that the app cannot repair on its own. If the other devices already show your lists correctly, this is a reasonable next step for the one device that is stuck.

If the problem remains after these checks, the device may be blocked by a network policy, a VPN, or a work or school management setting.

If the web version is the only place that fails, sign out there first, clear the browser session for Microsoft, then sign back in. That usually points to a stale web session rather than a device-wide sync problem.

How to check that Microsoft To Do is connected again

To confirm the fix worked, force a sync and compare the same list on more than one device.

1. Open a list on the device you just fixed and make a small change, such as adding a task named something obvious like sync test.
2. Open Microsoft To Do on another device or the web version and look for that same task.
3. Edit the task on the second device and check that the change returns to the first one.

A real fix means the app keeps syncing after you move away from the screen, close and reopen the app, and switch devices. A temporary refresh can make the app look healthy for a moment, then fail again a few minutes later.

If you want to be extra sure, sign out and back in once more after the test. If the task still appears everywhere, the connection is working again.

How to stop it from coming back

The best prevention is to keep the app, device, and account state simple.

• Keep Microsoft To Do updated on every device.
• Use one Microsoft account for your personal lists, and be careful not to mix it with a work or school account.
• If you use a VPN, test To Do without it when sync gets weird. Some VPNs, firewalls, and corporate policies block the Microsoft services To Do needs.
• Keep automatic date and time turned on.
• If you share a device, check which account is signed in before you edit anything.

If the problem returns only on a work or school device, the cause is often outside the app. In that case, the company network or device policy may be limiting sync, and the same steps that work at home may not be enough.

Conclusion

If Microsoft To Do still cannot connect after these checks, isolate whether the problem is your account, your network, or one device only. Start with service status and the account check, then work through the affected device. Once the same task appears on all your devices, you’re back to normal.

Frequently Asked Questions

Why does Microsoft To Do keep asking me to sign in?

That usually points to a stale session, a bad account token, or a network that blocks Microsoft authentication. Signing out and back in, or switching networks, often fixes it.

Can I lose my lists if I reinstall Microsoft To Do?

If your lists are already synced to your Microsoft account, reinstalling the app normally should not remove them from the cloud. The main risk is unsynced changes on the affected device, so check another device first if you can.

Why does To Do work on my phone but not my laptop?

That usually means the account is fine and the laptop has a local problem, such as a stale app session, outdated app version, wrong time settings, or a blocked network connection.