iPhone 上的 Wi-Fi 通话是在(Wi-Fi Calling on the iPhone)蜂窝连接不畅(areas with spotty cellular connectivity)的地区拨打和接听电话的绝佳替代方案。但是，有几个原因（例如与软件相关的故障、错误配置的设置以及与网络相关的问题）可能会导致 Wi-Fi 呼叫无法正常工作。
因此，如果当蜂窝信号显得微弱或不可用时Wi-Fi对您不起作用，下面的解决方案列表应该可以解决这个问题。
在 iPhone 上激活 Wi-Fi 通话
如果您刚刚完成了新 iPhone 的设置并且无法使用 Wi-Fi通话(Calling)功能，您必须确认该功能在 iOS 中处于活动状态。为此，请打开“设置”(Settings )应用并选择“蜂窝(Cellular)” 。然后，点击Wi-Fi 通话并打开(Wi-Fi Calling)此 iPhone 上的 Wi-Fi 通话(Wi-Fi Calling on This iPhone )旁边的开关（如果禁用）。
注意：(Note:)如果iPhone 的蜂窝网络设置中没有Wi-Fi 通话(Wi-Fi Calling)功能，请查看Apple 的无线运营商支持和功能页面(Apple’s Wireless Carrier Support and Features page)以确认您的运营商支持该功能。
(Activate Wi-Fi Calling)为其他设备激活 Wi-Fi 通话
您的蜂窝服务提供商还可能允许您使用与 iPhone 相同的Apple ID登录的任何 iOS 或 macOS 设备通过(Apple ID)Wi-Fi拨打电话。如果你不能这样做，你可能还没有激活相关设置。
在 iPhone 上，前往“设置”(Settings ) > “蜂窝(Cellular )网络” > “ Wi-Fi 通话” ，然后打开“(Wi-Fi Calling)为其他设备添加 Wi-Fi 通话”(Add Wi-Fi Calling For Other Devices)旁边的开关。
然后，返回上一个屏幕，点击其他设备上的通话(Calls on Other Devices)并打开您希望使用该功能的每台Apple设备旁边的开关。
重启 iPhone
尝试重新启动您的 iPhone。这通常有助于解决阻止 Wi-Fi 通话等功能正常工作的小问题。但是，由于 iOS 没有直接重启设备的选项，因此您必须在重新打开之前手动将其关闭。
为此，请前往“设置”(Settings ) > “通用(General )” > “关机”(Shut Down)，然后滑动电源(Power )图标以关闭 iPhone。然后，按住侧面(Side )按钮重新启动它。
弹出并重新插入 SIM
如果您的运营商支持 Wi-Fi 通话，但您可以看到打开它的选项，请尝试弹出SIM 卡(SIM)并将其重新插入您的 iPhone。这通常可以作为让它出现的快速解决方案。
使用SIM 卡(SIM)弹出工具或弯曲的回形针取出 iPhone 的SIM卡托。然后，在重新安装之前重新启动设备。
更新运营商设置
您的运营商会发布有助于解决错误和引入新功能的定期更新。iOS 会自动安装它们。但如果尚未应用最新更新，您可以自行强制安装。
为此，请转到设置(Settings )> 常规(General )>关于(About)并等待最多一分钟。如果您收到运营商设置更新(Carrier Settings Update )提示，声称有可用更新，请点击更新(Update)。
更新 iOS
更新 iOS 可以快速解决由系统软件的错误迭代引起的与 Wi-Fi 通话相关的问题。因此，请转到“设置”(Settings ) > “通用(General )” > “软件更新”(Software Update )，然后选择“下载并安装(Download and Install)”以让您的 iPhone 快速上手。如果 iOS 更新似乎停止或失败，您可以采取一些措施来修复卡住的 iOS 更新(there are things you can do to fix stuck iOS updates)。
禁用低数据模式
如果您为 Wi-Fi 连接打开了低数据模式(Low Data Mode)，最终可能会阻碍 Wi-Fi 相关功能（例如Wi-Fi 通话）(Wi-Fi Calling—from)正常工作。要关闭它，请转到设置(Settings )> Wi-Fi并禁用Wi-Fi 网络信息(Info )窗格下的低数据模式(Low Data Mode)选项。
检查与 Wi-Fi 相关的问题
如果您的 iPhone 上的Wi-Fi 通话(Wi-Fi Calling)设置正确，并且您已排除任何可能阻止其工作的冲突设置，最好检查您的 Wi-Fi 连接是否有问题。
因此，首先转到设置(Setting )> Wi-Fi。如果您注意到 Wi-Fi 符号或“无 Internet 连接”标签顶部有感叹号，则表明存在问题。
您可以尝试忘记并重新加入同一网络来解决问题。为此，请点击Wi-Fi网络并选择忘记此网络(Forget This Network)。然后，选择相同的网络并输入其密码以重新连接。
如果您没有发现任何异常情况，请尝试使用Safari浏览互联网。如果页面加载缓慢或完全失败，请继续进行其余修复。
打开/关闭飞行模式
打开和关闭飞行模式(Airplane Mode)是解决iPhone 上Wi-Fi问题的快速方法。(Wi-Fi)为此，请打开 iPhone 的控制中心(Control Center)并点击飞行模式(Airplane Mode)图标。几秒钟后点击相同的图标来跟随它。
或者，您可以使用设置应用程序中的(Settings )飞行模式(Airplane Mode)开关来启用和禁用飞行模式(Airplane Mode)。
软重置路由器
软重置路由器(Soft-resetting the router)还可以帮助解决与Wi-Fi的随机连接相关的问题。因此，如果它位于物理上可访问的位置，请尝试这样做。如果没有，您可能需要更新 iPhone 的 Wi-Fi 租约(renew the iPhone’s Wi-Fi lease)。
更改 DNS（域名服务）
(Popular DNS services)在 iPhone 上 使用Wi-Fi 通话时，(Wi-Fi Calling)流行的 DNS 服务（例如Google DNS和OpenDNS ）可能会为您的蜂窝帐户提供更好的连接。
要更改 Wi-Fi 连接的DNS服务器，请打开设置(Settings )应用程序并转到Wi-Fi。然后，选择网络信息窗格下的(Info )配置 DNS(Configure DNS)选项，切换到手动(Manual)，然后输入Google DNS或OpenDNS服务器，如下所示：
谷歌 DNS(Google DNS)
8.8.8.8
8.8.4.4
开放式DNS(OpenDNS)
208.67.222.123
208.67.220.123
重置网络设置
如果 Wi-Fi 通话不起作用，请尝试在 iPhone 上执行网络设置重置。(performing a network settings reset)这应该可以解决蜂窝和 Wi-Fi 的任何潜在问题。为此，请转到“设置”(Settings ) > “常规(General )” > “重置(Reset )” ，然后选择“重置网络设置”(Reset Network Settings)。
重置过程后，您必须重新连接到任何Wi-Fi网络。(Wi-Fi)您的蜂窝服务设置应在后台自动更新。
联系您的无线运营商
如果Wi-Fi通话仍然无法正常工作，请尝试联系您的无线运营商。他们应该能够帮助您找出问题所在并提出其他建议，以帮助修复iPhone 上的Wi-Fi 通话。(Wi-Fi Calling)
Wi-Fi Calling Not Working on iPhone? Try These Fixes
Wi-Fi Calling on the iPhone works as a terrific alternative to making and receiving phone calls in areas with spotty cellular connectivity. However, several reasons—such as software-related glitches, incorrectly configured settings, and network-related issues can prevent Wi-Fi calling from working.
So if Wi-Fi isn’t working for you when cellular signals appear weak or unavailable, the list of solutions below should fix that.
Activate Wi-Fi Calling on iPhone
If you just finished setting up a new iPhone and can’t get Wi-Fi Calling to work, you must confirm that the feature is active in iOS. To do that, open the Settings app and select Cellular. Then, tap Wi-Fi Calling and turn on the switch next to Wi-Fi Calling on This iPhone (if disabled).
Note: If Wi-Fi Calling isn’t available within your iPhone’s Cellular settings, check Apple’s Wireless Carrier Support and Features page to confirm that your carrier supports the functionality.
Activate Wi-Fi Calling for Other Devices
Your cellular provider may also allow any iOS or macOS devices that you’ve signed in to with the same Apple ID as your iPhone’s to make calls over Wi-Fi. If you can’t do that, you probably haven’t activated the relevant settings yet.
On the iPhone, head over to Settings > Cellular > Wi-Fi Calling and turn on the switch next to Add Wi-Fi Calling For Other Devices.
Then, go back to the previous screen, tap Calls on Other Devices and turn on the switches next to each Apple device you want the feature to work with.
Restart iPhone
Try restarting your iPhone. That usually helps resolve minor issues preventing features such as Wi-Fi Calling from working correctly. However, since iOS doesn’t have a direct option to reboot the device, you must manually shut it down before turning it back on.
To do this, go to Settings > General > Shut Down and slide the Power icon to power down your iPhone. Then, press and hold the Side button to restart it.
Eject and Reinsert SIM
If your carrier supports Wi-Fi calling but you can see the option to turn it on, try ejecting and reinserting the SIM to your iPhone. That often acts as a quick fix in getting it to show up.
Use a SIM ejector tool or a bent paper clip to take out the iPhone’s SIM tray. Then, restart the device before putting it back in.
Update Carrier Settings
Your carrier releases periodic updates that help resolve bugs and introduce new features. iOS installs them automatically. But if it’s yet to apply the latest update, you can force-install it yourself.
To do that, go to Settings > General > About and wait for up to one minute. If you receive a Carrier Settings Update prompt claiming an update is available, tap Update.
Update iOS
Updating iOS can quickly iron out Wi-Fi Calling-related issues induced by a buggy iteration of the system software. So go to Settings > General > Software Update and select Download and Install to get your iPhone up to speed. If an iOS update appears to stall or fail, there are things you can do to fix stuck iOS updates.
Disable Low Data Mode
If you’ve turned on Low Data Mode for your Wi-Fi connection, that can end up hindering Wi-Fi-related functionalities—such as Wi-Fi Calling—from working correctly. To turn it off, head over to Settings > Wi-Fi and disable the Low Data Mode option under the Wi-Fi network’s Info pane.
Check for Wi-Fi-Related Issues
If Wi-Fi Calling is set up correctly on your iPhone and you’ve ruled out any conflicting settings that might be preventing it from working, it’s best to check that there’s nothing wrong with your Wi-Fi connection.
So start by heading over to Setting > Wi-Fi. If you notice an exclamation mark atop the Wi-Fi symbol or a “No Internet Connection” label, that indicates an issue.
You can try forgetting and rejoining the same network to resolve the issue. To do that, tap the Wi-Fi network and select Forget This Network. Then, pick the same network and type in its password to reconnect.
If you don’t see anything unusual, try browsing the internet using Safari. If pages load slowly or fail altogether, move on with the rest of the fixes.
Turn Airplane Mode On/Off
Toggling Airplane Mode on and off is a quick method to fix issues with Wi-Fi on the iPhone. To do that, open the iPhone’s Control Center and tap the Airplane Mode icon. Follow that by tapping the same icon after a few seconds.
Alternatively, you can use the Airplane Mode switch within the Settings app to enable and disable Airplane Mode.
Soft-Reset the Router
Soft-resetting the router can also help fix random connectivity-related issues with Wi-Fi. So try doing that if it’s in a physically accessible location. If not, you may want to renew the iPhone’s Wi-Fi lease instead.
Change DNS (Domain Name Service)
Popular DNS services such as Google DNS and OpenDNS may offer better connectivity to your cellular account while using Wi-Fi Calling on the iPhone.
To change the DNS servers for your Wi-Fi connection, open the Settings app and go to Wi-Fi. Then, pick the Configure DNS option under the network’s Info pane, switch to Manual, and enter the Google DNS or OpenDNS servers as follows:
Google DNS
8.8.8.8
8.8.4.4
OpenDNS
208.67.222.123
208.67.220.123
Reset Network Settings
Try performing a network settings reset on your iPhone if Wi-Fi calling is not working. That should fix any underlying issues with both cellular and Wi-Fi. To do that, go to Settings > General > Reset and select Reset Network Settings.
You must reconnect to any Wi-Fi networks after the reset procedure. Your cellular service settings should update automatically in the background.
Contact Your Wireless Carrier
If Wi-Fi calling is still not working, try contacting your wireless carrier. They should be able to help you figure out what’s wrong and make additional suggestions that can help fix Wi-Fi Calling on the iPhone.
