Galaxy S4 invalid number when sending text message (SMS), other SMS issues

Sending and receiving text messages is one of the core functions of any smartphone today. When that function is taken away due to a phone or network glitch, it’s understandable to get annoyed. Below are some of #GalaxyS4 text messaging problems shared by our readers. We hope that the solutions suggested in this post can be of help to other users with similar issues.



If you have your own Android issue, don’t hesitate to use the link provided at the bottom of this page.



Problem #1: Galaxy S4 unable to reply to text message as recipient’s number becomes invalid

When I text my son, I text him from the correct number. When he responds, it displays a different phone number (one number off).  It shows up in a different thread and I have to go back to the thread with the right number to text back. I have tried to delete his contact and set it up again, tried to reboot my phone,  took battery and SIM out and still happens. When he texts other people his number shows up correctly.  So I figure it’s my phone. —Ami

Solution: Hi Ami. This is not a phone problem but an AT&T one. This forum thread shows the same phenomenon is happening on other Android phones and iOS devices from AT&T so that is a clear indicator of an on-going network issue. Please work with your carrier (AT&T) for more assistance regarding this matter.

Problem #2: Samsung Galaxy S4 slow when sending SMS

History and facts:

  1. Owned used Galaxy S4 since April 2015. All features working just fine.
  2. Texting apps installed since Day 1 of owning phone are Line, WhatsApp, and Hangout. I used the built-in texting app the most, followed by Line, and WhatsApp. I never used Hangout; it was just installed just in case.
  3. I was able to successfully send and receive texts and pictures from phone numbers and emails using data AND wi-fi for ALL texting apps.
  4. My service provider is T-Mobile.

Problem: Today, August 25th, 2015, I experienced problems with my built-in messenger app. Based on data AND wi-fi, I would send a text message to a phone number, and it would always be “sending”. The circle would be spinning, but it would not show up as “successfully sent” instantly like it did before. I would text various people as guinea pigs and time stamp when I sent the texts. The recipients would receive my text on their phone two minutes later, while my text would still be spinning, or seen as successfully sent 10 minutes later. I would also receive delayed texts from them about 5 minutes later on average, if at all. The weird thing is that using the same built-in messenger app, I was able to send texts and pictures to all email addresses. It would show up as “sent” immediately on my phone, and all email content were received instantly. The 3rd party texting apps were not affected at all. WhatsApp and Line were just fine as well. It was only the phone numbers that are affected by this delay from the built-in messenger app.


  • Switched between wi-fi and data at home AND work to no avail
  • Restarted phone several times to no avail
  • Cleared cache AND data to no avail
  • Switched out three batteries to no avail
  • Let phone rest for a few hours to no avail

I have now switched to Hangout as my default messaging app. It works just fine. I just want to know what happened to the built-in app and why only phone numbers are affected with this abrupt problem. — Dao

Solution: Hi Dao. We’ve noticed this problem with other Samsung devices before but we are still in the process of collecting more data to determine the common denominators in every case so we cannot give you any definite answer to the possible cause. Among the solutions we provide include clearing the app’s cache and data (done), clearing the system cache, restarting in safe mode, uninstalling apps, and doing a factory reset.

These are standard firmware/software solutions and any of them should help you address the trouble.

Delete Galaxy S4 cache partition

Wiping the system cache is often an effective solution for any app-related problem as it ensures that the devices is using a clean set of cache afterwards. Here’s how you do it:

  • Turn the phone off completely.
  • Press and hold the Volume Up, Home and Power buttons.
  • Release the Power button when the phone vibrates but continue holding on to the Volume Up and Home buttons.
  • When the Android System Recovery screen appears, release both the Home and Volume Up buttons.
  • Using the Volume Down key, highlight ‘wipe cache partition.’
  • Press the Power button to select the option.
  • The phone will automatically restart once cache data are wiped out.

Reboot the Galaxy S4 in safe mode

If your Galaxy S4 takes a long time to send text messages after updating an app or installing a new one, rebooting your phone in S4 is a good troubleshooting step to do. All third party apps are prevented from running when you boot your phone in safe mode. If the problem does not occur while in this environment, you should start uninstalling your apps until the issue is completely gone. If you haven’t tried doing safe mode before, just follow these steps:

  • Press and hold the Power button.
  • Once the Samsung Galaxy S4 logo appears on the screen (assuming the phone responds to Power key press), release the Power button.
  • As soon as you release the Power button, press and hold the Volume Down key.
  • Continue holding the Volume Down key until the phone has completed the reboot process.
  • If you can read ‘Safe Mode’ at the bottom left corner of the screen, release the Volume Down key. Otherwise, repeat the process until you can boot the phone to Safe Mode.

Uninstall third party apps

If you suspect that one of your apps is the culprit, try to uninstall the most recently installed until the root cause has been isolated.

Wipe the phone clean

Restoring the phone’s defaults is one of the most effective solutions when it comes to all sorts of firmware/software ills. Because this procedure will delete everything from your phone’s internal storage (but not the SD card contents), make sure to create a copy of your files before doing it. Here’s how:

  • Turn the phone off completely.
  • Press and hold the Volume Up, Home and Power buttons.
  • Release the Power button when the phone vibrates but continue holding on to the Volume Up and Home buttons.
  • When the Android System Recovery screen appears, release both the Home and Volume Up buttons.
  • Using the Volume Down key, highlight wipe data / factory reset.
  • Press the Power button to select it.
  • Using the Volume Down button again, highlight delete all user data.
  • Press the Power key to select it.
  • Once the reset is complete, choose Reboot system now.
  • Press the Power button to restart the phone.

Problem #3: Galaxy S4 unable to send text messages and access voicemail after an update

I have AT&T through Net10 & ever since my phone was updated by Samsung, I can receive text messages but cannot send them, and I cannot access my voicemail. When I enter my passcode, it just keeps saying “please enter your passcode.” It shows that 4G is active. I’ve tried a factory reset, removing the battery & SIM card with no change. There is a message when I swipe down the status bar that “”The SIM card is not from Verizon”” but it has always shown that. I went in and entered new APN settings for Net10/ATT from what I found on the internet (which is what I had to do when I first got the phone)

Name: Net10

APN: tfdata 

port: 80  MMSC: 

multimedia msg port: 80 

MCC 310 

MNC: 410 

APN: IPv4,

the rest are blank. I hope you can help me or direct me to where I need to go to fix the issue, thanks!! — Denise

Solution: Hi Denise. If this problem happens after updating the phone’s operating system, the most likely reason must be a misconfiguration of the phone’s APN settings. We recommend that you contact your network service provider to let them know about the problem. You want to get the correct APN settings directly from them. Some APN values can change from time to time so make sure that you have updated APN settings in your device. You also need to check with your carrier why your voicemail service is failing.

Problem #4: Galaxy S4 unable to send group text and MMS

Ever since I got my phone I have not been able to send images to others and I have not been able to send multimedia texts and group texts. When I try to send a photo the text fails and the messages “oops low account balance” shows up. I can receive other group messages and images if I have access to the internet to download it or my unlimited 4G data is turned on. My mother’s partner has the exact same phone as I do with the exact same phone plan (we are under a family plan with Credo) and she has no problem sending photos or group texts. Is there a solution to this? — Laya

Solution: Hi Laya. Just like Denise above, you need to contact your network service provider to ensure that there’s no account- or billing-related restriction that prevents your device from sending MMS. You also need to ensure that your device has the correct APN settings.

Problem #5:  Unlocked Verizon Galaxy S4 unable to send SMS. text message after Lollipop update

I have an unlocked Galaxy from Verizon. I switched to T-Mobile. Everything worked fine until Lollipop update. Now I cannot SEND SMS text. I can receive them but NOT reply. I can receive and send MMS messages. In order to reply to a text I need to convert it to MMS, I tried third party text apps but none of them worked.- Textra, Hangouts, etc.

T-Mobile has been of no help. They say it is a VZ phone and VZ will not help because I am now with T-Mobile. Any suggestions? — Bob

Solution: Hi Bob. The Lollipop update may have changed the network settings of your phone including the Message Center value. Make sure that the message center number shows +12063130004. To manually change the message center number, follow the steps below:

  • Go to Settings.
  • Tap Messaging.
  • Tap the Menu icon.
  • Tap Settings.
  • Tap Message Center.
  • Enter the T-Mobile message center number.
  • Tap OK.


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