Galaxy S9 Plus keeps showing “Message not delivered” after sending SMS successfully

Hello Android fans! We’ve been getting a lot of reports lately about some devices, and not just the #GalaxyS9 and #GalaxyS9Plus devices, showing “Message not delivered” bug everytime an SMS or MMS is sent out. The thing is, these messages are actually delivered, as shown by one of our S9 owners below. While we think that this issue may be app-related, we want to ensure that all possible angles are covered. We don’t know how extensive this problem is, or whether it’s only in one specific region or carrier so the more solution options you can try, the better. If you happen to be having this issue on your own S9 or whatever Android device you may have, be sure to follow the list of solutions in the order provided below.

Today’s problem: Galaxy S9 Plus keeps showing “Message not delivered” after sending SMS successfully

I have a Samsung S9+ and my wife has a Galaxy S6 Edge and when i message her it shows me the error message “message not delivered” even though she receives it. This only happens when sending her SMS. — Muldoon941

Solution: Hi Muldoon941. This problem might be caused by a bug either in your device, or in your network. To troubleshoot it, you have to do a number of steps. Before you try drastic troubleshooting steps, be sure that you restart your phone. Some bugs may only last as long as the current device is running so if you shut it down, said bug may cease to exist. If you’ve already restarted your S9 Plus normally, consider simulating a “battery pull.” Here’s how:

1. Press and hold the Power + Volume Down buttons for approximately 10 seconds or until the device power cycles. Note: Allow several seconds for the Maintenance Boot Mode screen to appear.
2. From the Maintenance Boot Mode screen, select Normal Boot. Note: Utilize the volume buttons to cycle through the available options and the lower left button (below the volume buttons) to select. Also, allow up to 90 seconds for the reset to complete.

Remember, it’s always good practice to regularly restart your device. It won’t only fix some bugs but it can also prevent them from developing, as well as helping the system to run fresh in general.

Solution #1: Force stop messaging app

To begin the proper troubleshooting stage, the first thing that you want to do is to quit the app. Like a device restart, quitting the app may potentially address a bug that may be running when your messaging app is on. Messaging apps like the stock Samsung Messages always run in the background so stopping it may also prevent the bug from coming back up. To quit an app, follow these steps:

1. From a Home screen, touch and swipe up or down to display all apps.
2. From a Home screen, navigate: Settings > Apps.
3. Locate then tap the messaging app you’re using.
4. Tap FORCE STOP button.
5. Reboot your phone to refresh its memory.

Solution #2: Clear cache and data

If quitting your messaging app won’t change anything, the next troubleshooting step that you want to do is to ensure that you delete its cache and data. Each of these procedures must be done separately — by clearing the cache first, followed by clearing of data. Wiping your data of a messaging app will result to loss of messages so be sure to back your SMS first before doing it. If you’re using Samsung’s Messages app, you can utilize Samsung’s cloud service to save your SMS under Settings > Cloud and accounts > Samsung cloud. Alternatively, you can use Samsung Smart Switch to back everything up, or just your messages.

If you’re using a third party messaging app, or your carrier’s messaging app, find a way to back them up.

Then, once you’re ready, begin clearing the messaging app’s cache. Here’s how:

1. From a Home screen, touch and swipe up or down to display all apps.
2. From a Home screen, navigate: Settings > Apps.
3. Locate then tap the messaging app you’re using.
4. Tap Storage.
5. Tap CLEAR CACHE.
6. Reboot your phone to refresh its memory.

After restarting your device, check for the issue. If it remains, repeat steps 1-4, then tap Clear Data button.

Solution #3: Wipe cache partition

Another good possible solution to your issue is wiping the cache partition. While not all issues are fixed by doing this, many minor, unexplained, and seemingly random problems are sometimes addressed by clearing the cache partition. This partition is where the system cache is stored. By clearing it, you’re telling Android to delete the system cache and rebuild it.

To clear the cache partition of your S9 Plus:

1. Turn off the device.
2. Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
3. When the Android logo displays, release all three keys.
4. An ‘Installing system update’ message will show for 30 – 60 seconds before the Android system recovery menu options appear.
5. Press the Volume down key several times to highlight wipe cache partition.
6. Press Power key to select.
7. Press the Volume down key to highlight yes, them and press the Power key to select.
8. When the wipe cache partition is complete, Reboot system now is highlighted.
9. Press the Power key to restart the device.

Solution #4: Reset network settings

Some of your phone’s functionalities are deeply tied to basic network setup so at times, clearing the current network configuration may help. If you are yet to clear your S9’s network settings, here are the steps:

1. Open Settings app.
2. Tap General management.
3. Tap Reset.
4. Tap Reset Network Settings.
5. Tap RESET SETTINGS button.

Solution #5: Use another messaging app

Should the issue still remain at this point, it’s possible that there may be a problem with the messaging app itself. To see if that’s the case, try using another app. For example, if you’re using your carrier-provided messaging app, try switching to the stock Samsung Messages app and see how messaging works. If you’re now using the Messages app from Samsung, then you can use other messaging apps from Google Play Store.

Solution #6: Factory reset

Ideally, factory reset should never be performed for an issue like this but you ought to do it should all our suggestions above won’t help at all. Factory reset in this case will address an operating system bug that may have developed over time. Before you factory reset your S9, be sure to back your files up to avoid losing data.

Once you’re ready, follow these steps to factory reset your S9:

1. Turn off the device.
2. Press and hold the Volume Up key and the Bixby key, then press and hold the Power key.
3. When the green Android logo displays, release all keys (‘Installing system update’ will show for about 30 – 60 seconds before showing the Android system recovery menu options).
4. Press the Volume down key several times to highlight ‘wipe data / factory reset’.
5. Press Power button to select.
6. Press the Volume down key until ‘Yes — delete all user data’ is highlighted.
7. Press Power button to select and start the master reset.
8. When the master reset is complete, ‘Reboot system now’ is highlighted.
9. Press the Power key to restart the device.

Solution #7: Contact your carrier

Finally, you should not hesitate to let your carrier know about this problem because after all, this involves their system. All the solutions provided above are meant to address a host of possible phone problems. Since nothing has worked so far, we can only assume that the bug must be network-related. Be sure to mention what specific phone troubleshooting you’ve done to your carrier so they’ll know that you’ve already covered everything before contacting them.