Android用户经常遇到连接问题或设备上的无效MMI代码是很常见的。这可能真的很烦人，因为它只是意味着在修复此错误之前您将无法发送任何短信或拨打任何电话。
MMI 代码，也称为人机界面(Man-Machine Interface)代码，是您在拨号盘上输入的数字和字母字符以及 *（星号）和 #（哈希）的复杂组合，用于向客户端发送请求。检查帐户余额、激活或停用服务等的提供商。
出现此MMI代码错误的原因有很多，例如SIM身份验证问题、运营商提供商薄弱、字符位置错误等。
为了解决这个问题，我们记下了解决连接问题或无效MMI代码的方法列表。那么，让我们开始吧！
修复连接问题或无效的 MMI 代码(Fix Connection Problem or Invalid MMI Code)
1.重新启动您的设备(1. Restart your device)
只需重新启动您的设备(reboot your device)并希望获得更好的结果。通常这个技巧可以解决所有常见问题。重启/重启手机的步骤如下：
1.长按电源键(power button)。在某些情况下，您可能必须按下volume down + home button，直到弹出菜单。无需解锁手机即可执行此过程。
2.现在，在列表中选择restart/reboot选项，等待手机重启。
检查代码错误何时仍然发生。
2.尝试重启到安全模式(2. Try rebooting to the safe mode)
此步骤将切断所有第三方应用程序或任何在后台运行的干扰手机功能的外部软件。它将仅通过运行库存的Android程序来帮助您的设备解决问题。此外，执行此技巧非常简单易行。
开启安全模式的步骤：
1. 按住设备的电源按钮(power button)。
2. 从选项中，点击重新启动(Restart)。
3. 在您的显示屏上，您将看到一个弹出窗口，询问您是否要重新启动到安全模式(Reboot to safe mode)，点击确定(OK)。
4.您的手机现在将启动到安全模式(safe mode )。
5.此外，您还可以在主屏幕的左下角看到写着的安全模式。(safe mode)
另请阅读：(Also Read:) 修复 WhatsApp 的常见问题(Fix Common Problems with WhatsApp)
3.修改前缀代码(3. Make changes in the prefix code)
您可以通过修改和更改前缀代码来简单地修复连接问题(Problem)或设备上的无效MMI代码。您需要做的就是在前缀代码(prefix code)的末尾加一个逗号。添加逗号将迫使操作员忽略任何错误并执行任务。
我们列出了两种不同的方法：
方法一：(METHOD 1:)
假设前缀代码是*3434*7#.现在，在代码末尾加一个逗号，即*3434*7#,
方法二：(METHOD 2:)
相反，您可以在 * 符号后添加+*+3434*7#
4. 通过 IMS 激活无线电和 SMS(4. Activate the radio and SMS over IMS)
通过IMS打开SMS并激活无线电也有助于解决此问题。为此，请执行以下步骤：
1. 打开拨号盘并输入*#*#4636#*#*。您不一定需要按下发送按钮，因为它会自动闪烁服务模式。(service mode.)
2. 点击服务模式(service mode)，然后点击设备信息(Device information )或电话信息( Phone information)。
3. 按运行 Ping 测试(Run Ping test )按钮，然后选择关闭无线电(Turn Radio Off)按钮。
4. 选择通过 IMS 开启 SMS 选项。(Turn on SMS over IMS option.)
5. 现在，您只需重新启动(reboot)设备即可。
另请阅读：(Also Read:) 如何在您的 Android 手机上卸载或删除应用程序(How to Uninstall or Delete Apps on your Android Phone)
5.检查网络设置(5. Keep a check on network settings)
如果您的信号微弱且不稳定，您可能需要检查您的网络设置。您的手机渴望获得更好的信号，因此它往往会在3G、4G 和 EDGE(3G, 4G, and EDGE)等之间不断切换。在这里稍作调整，希望能解决您的问题。以下是执行此操作的步骤：
1. 进入设置(Settings)。
2.导航到网络连接(Network Connection)并点击它
3. 现在，点击移动网络(Mobile networks)选项并查找网络运营商。(Network operators.)
4. 最后，搜索网络运营商并点击您的无线提供商(Wireless provider)。
5. 再重复此过程 2-3 次。
6. Reboot/restart您的设备，希望它会再次开始工作。
6. 检查您的 SIM 卡(6. Check your SIM card)
最后，如果没有任何效果，请查看您的SIM 卡，可能是它造成了问题。大多数情况下，您的SIM卡因不断拔出和重新插入而损坏。或者，也许它被粗略地切割了。无论是什么原因，您的SIM卡都可能已损坏。我们建议在这种情况下更换并获得新的SIM卡，以免为时已晚。(SIM)
对于使用双SIM 卡(SIM)智能手机的用户，您必须在两者之间进行选择：
方法一：(METHOD 1:)
停用其中一张(Deactivate one)SIM卡(SIM)并启用您用来发送MMI代码的那张。有时，如果您同时使用两个手机，您的手机可能无法使用正确的SIM卡。
方法二：(METHOD 2:)
1. 进入设置(Settings)，找到SIM 卡和移动网络(SIM cards and mobile networks)。
2. 找到手机的双SIM 卡设置(SIM settings)，然后点击语音通话(Voice call )设置。
3. 将出现一个弹出列表，要求您在“始终使用 SIM 1”、“SIM 2”(Always Use SIM 1, SIM 2, )或“每次询问”之间进行选择。(Ask every time.)
4. 选择总是询问(Always Ask)选项。现在，在拨打MMI代码时，您的手机会询问您要使用哪个SIM 卡。(SIM)选择正确的一个以获得正确的结果。
如果您拥有单个 SIM 卡(single SIM card)设备，请尝试在清洁和吹气后拔出并重新插入您的SIM卡。(SIM)看看这个技巧是否有效。
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如果每次拨打前缀代码时都会弹出连接问题或无效的MMI代码错误，这可能会有点麻烦。希望(Hopefully)这些技巧可以帮助您。如果您的手机仍然存在问题，请尝试联系您的服务提供商或客户服务以获得更好的指导。
Fix Connection Problem or Invalid MMI Code
It is quite common for Android users to face a connectіon problеm or the invalid MMI cоde on their devices everу so often. This can be rеally annoуing because it simply means that you won’t be able to send any text meѕѕages or make any calls until this error is fixеd.
The MMI code, also known as the Man-Machine Interface code is a complex combination of the digits and alphabetical characters which you enter on your dial pad along with the * (asterisk) and # (hash) in order to send a request to the providers for checking the account balance, activating or deactivating the services, etc.
This MMI code error occurs because of many reasons such as SIM authentication issues, weak carrier providers, wrong position of the characters, etc.
To solve this issue, we have jotted down a list of ways to fix the connection problems or the invalid MMI code. So, let’s get started!
Fix Connection Problem or Invalid MMI Code
1. Restart your device
Simply reboot your device and hope for better results. Often this trick resolves all the common issues. The steps to reboot/restart your phone are as follows:
1. Long-press the power button. In some cases, you may have to press the volume down + home button until a menu pops up. It is not necessary to unlock your phone to do this process.
2. Now, select the restart/reboot option among the list and wait for your phone to restart.
Check when the code error is still occurring.
2. Try rebooting to the safe mode
This step will cut off all the third-party apps or any external software running in the background disturbing your phone’s functioning. It will help your device to troubleshoot the issue by only running the stock Android programs. Also, it is quite simple and easy to do this trick.
Steps to turn on the safe mode:
1. Press & hold the power button of your device.
2. From the options, tap on Restart.
3. On your display, you will see a pop-up asking you if you want to Reboot to safe mode, tap on OK.
4. Your phone will be booted to the safe mode now.
5. Also, you’d be able to see the safe mode written at the bottom-left corner of your home screen.
Also Read: Fix Common Problems with WhatsApp
3. Make changes in the prefix code
You can simply fix the connection Problem or the invalid MMI code on your device by modifying and changing the prefix code. All you need to do is put a comma at the end of the prefix code. Adding a comma will force the operator to overlook any error and perform the task.
We have listed down two different ways to do so:
METHOD 1:
Supposedly, the prefix code is *3434*7#. Now, put a comma at the end of the code, i.e.*3434*7#,
METHOD 2:
Instead, you can add the + symbol after the * sign i.e. *+3434*7#
4. Activate the radio and SMS over IMS
Turning on the SMS over IMS and activating the radio can also help out in fixing this issue. Perform the following steps to do so:
1. Open your dial pad and type *#*#4636#*#*. You don’t necessarily need to press the send button as it will automatically flash the service mode.
2. Tap on service mode and click on either Device information or Phone information.
3. Press the Run Ping test button and then select the Turn Radio Off button.
4. Select Turn on SMS over IMS option.
5. Now, you just have to simply reboot your device.
Also Read: How to Uninstall or Delete Apps on your Android Phone
5. Keep a check on network settings
You might want to check your network settings if your signal is weak and unstable. Your phone longs for a better signal because of which it tends to shift constantly between 3G, 4G, and EDGE, etc. A little tweaking here and there will hopefully fix your issue. Following are the steps to do so:
1. Go to the Settings.
2. Navigate to Network Connection and tap on it
3. Now, tap on the Mobile networks option and look for the Network operators.
4. Finally, search the network operators and tap on your Wireless provider.
5. Repeat this process for another 2-3 times.
6. Reboot/restart your device and hopefully, it will start working again.
6. Check your SIM card
Finally, if nothing really works, take a look at your SIM card, maybe it is the one creating problems. Mostly, your SIM card is damaged because of continuous pulling out and reinsertion. Or, maybe it was cut roughly. Whatever the reason may be, your SIM card is probably corrupt. We recommend changing and getting a new SIM card in this kind of situation before it is too late.
For the ones using a dual SIM smartphone, you have to choose between the two:
METHOD 1:
Deactivate one of the SIM cards and enable the one that you’re using to send the MMI code. Sometimes your phone may not use the correct SIM card if you have both of them performing together.
METHOD 2:
1. Go to the Settings and find SIM cards and mobile networks.
2. Find the phone’s dual SIM settings and then tap on the Voice call Settings.
3. A pop-up list will appear, asking you to choose between Always Use SIM 1, SIM 2, or Ask every time.
4. Select Always Ask option. Now, while dialing the MMI code, your phone will ask you which SIM you want to use. Select the correct one for proper results.
If you own a single SIM card device, try pulling out and reinserting your SIM card after cleaning and blowing on it. See if this trick works.
Recommended: Fix Android Wi-Fi Connection Problems
It can get a little pesky if the connection problem or invalid MMI code error pops up every time you dial a prefix code. Hopefully, these hacks will help you out. If your phone is still creating a problem, try contacting your service provider or customer care service for better guidance.
