How to fix Microsoft Teams not working on an iPhone

5 steps to troubleshoot Microsoft Teams on an iPhone

There are some common problems that users can run into with Teams, and many of them have more than one possible cause. A user might experience app crashes, have trouble logging in or not receive Teams notifications. In any case, IT administrators should start the troubleshooting process by making sure that it's not the result of a simple misconfigured setting. Conversely, IT should make sure that it's not a wider outage or known issue that will affect other users as well.

IT and users can then get to the root of the issue by checking the internet connection, trying the desktop app, looking at the smartphone's hardware resources, installing updates or clearing app data.

1. Check the iPhone's internet connection

When a Teams issue arises on an iPhone, admins should first find out whether the device has good internet connectivity. Inadequate network bandwidth can cause issues ranging from choppy audio and video to Teams failing to sync. Low bandwidth can also cause a delay in receiving messages.

If the device is connected to the internet using a cellular link, try an internet speed test to confirm that the iPhone's connection is fast enough to support Teams. Users can also try temporarily connecting the phone to a Wi-Fi network to see if the problem goes away.

After determining how much internet bandwidth is available on the iPhone, the next step is to compare the measured bandwidth to Microsoft's requirements for Teams. The bandwidth requirements vary based on the type of session. For example, a one-to-one audio call requires a minimum of 10 Kbps. Microsoft recommends having at least 58 Kbps, with 76 Kbps offering the best performance. On the other hand, if the user is trying to make a video call, the bandwidth requirements go way up. For an optimal experience, a user needs 4,000 Kbps of bandwidth to complete a video call. This is also the amount of bandwidth that Microsoft considers optimal for video meetings and screen sharing.

If the user does have adequate bandwidth but is still having issues with Teams, it's a good idea to run the Microsoft 365 network connectivity test. This tool measures internet connectivity speed, as well as the speed at which the device can communicate with Microsoft 365 servers. It's possible that the user's internet connection is fine, but Microsoft is having network performance issues.

2. Try using the desktop app

If Teams begins working properly on the desktop, the problem is either related to the user's iPhone or to the mobile app.

After ruling out network issues as the source of the problem, the next step is to install the Teams app onto a desktop computer. Assuming that this computer is connected to the same Wi-Fi network as the user's iPhone, installing the desktop app can help determine whether the problem is related to the device or the app. When the user logs into Teams on the desktop computer, they are still connected to the same network, and they are still in the same user account. The only thing that has changed at that point is the user's device.

If Teams begins working properly on the desktop, the problem is either related to the user's iPhone or to the mobile app. If the user also has problems with the desktop app, however, the problem is most likely related to the user's account.

3. Check the iPhone's hardware resources

At this point in the troubleshooting process, IT should make sure that the iPhone is not starved for hardware resources. Low memory or storage space can cause various issues. It's especially common for the Teams app to run slowly or to lock up altogether if the phone is running low on resources.

To find out how much storage space is available on the iPhone, open Settings and tap General, followed by iPhone Storage.

There isn't a way to check an iPhone's memory usage without downloading a third-party tool, which often requires the use of developer mode. Instead, swipe up from the bottom of the screen. The screen will show all the apps that are running in the background. A large number of background apps translates directly to higher memory usage. Users can close the background apps by swiping each app up to the top of the screen. Another option is to simply reboot the phone.

Users should also confirm that the phone is not running in low power mode. This setting can save battery life, but it can cause serious performance and reliability issues for Teams. To check, open Settings and then tap Battery. Make sure that the Low Power slider is turned off.

4. Install available updates

A wide range of performance issues can occur if an iPhone isn't running the latest version of iOS. Check if any software updates are available. Additionally, look for any available updates for the Teams app or any other Microsoft 365 apps.

5. Clear the app cache

If the previous troubleshooting steps don't fix Microsoft Teams, the user might need to clear the app cache. Clearing the Teams cache forces the app to refresh its content. This can solve many common issues, including synchronization problems, poor performance and user logout at random times.

The iOS Teams app does not contain the same Clear Cache option as the desktop app. Even so, there are several options to clear Teams data. Tap on the user's profile icon in the top-right corner of the screen in Teams. Then, tap Settings, followed by Data and Storage. The Data and Storage screen contains options to clear downloaded files, clear history and clear app data.

Clearing the data in this way should suffice in most cases. If not, the best thing to do is uninstall and then reinstall Teams.

Brien Posey is a former 22-time Microsoft MVP and a commercial astronaut candidate. In his more than 30 years in IT, he has served as a lead network engineer for the U.S. Department of Defense and a network administrator for some of the largest insurance companies in America.