Fixing Error 28 sending SMS messages using the Google Messaging App

[AthloniumXIX]

Hello everyone! Just thought I would share some information about fixing Error 28 using SMS on the stock Google Messaging app. I had this problem on the Google Pixel 7 Pro and the OnePlus 10 pro but this solution can be used on any Android device.

I had this error message for a while and couldn't send any SMS text messages to any number (including trying to message to people with different providers) and after many hours searching through the Google Search Engine... I managed to peice together the solution.

Error 28 is a SMSC problem, where the message center number is incorrect for the tariff type (I am on PayAsYouGo, Google defaults to the Pay Monthly tariff SMSC) so I had to manually enter my SMSC number in a hidden menu to get SMS messaging working again. As you cannot change it in the messaging app itself.

The solution:

1. Tap *#*#4636#*#* into the Stock Android Phone App... After the last astericks is typed, the Android Testing Menu will appear on the screen.
2. Tap Phone information and Scroll down to the bottom of the menu and locate the "SMSC" option.
3. Enter the relevant SMSC number in the input field, then tap Update after you tapped the number in.
4. For customers on Pay & Go tariffs, your message centre number is +447802092035.

This will then stop Error 28 on the messaging app.

The one thing I have found is that after every software update from Google themselves, the SMSC is reset to the Contract one. Just rinse and repeat.

[Dman]

Hi there,

Thanks for the info, but I must be a bit stupid. What do you mean by the Stock Android Phone App? I've looked through the apps and in settings, but xant find it. 

Thanks

Darren

[Enlli]

@Dman It's the app you use to dial out.

Usually green Icon with a telephone handset symbol 

[Dman]

Thank you Enlli,

I got close! When I put in the number (for pay monthly), I get a message of 'update error'. So frustrating! 

I'll have another look around to see if I got the number wrong.

Thanks for pointing me in the right direction! 

[L_G]

Hi Dman, happened to me too and managed to fix it unintentionally!

I followed the instructions above but before entering the SMSC number, I first changed the 'mobile info refresh rate' to 'immediate' and then entered the SMSC number. The update error message did come up and I pressed 'refresh' and a number popped up. It might look odd as it has quotation marks and extra digits. Don't change that. All you do is replace that 'mobile number' with the SMSC number. Don't change anything else! Leave the quotation marks, commas,extra digits at the end etc as they are and then press 'Update' . Not sure what phone you are using but hope it helps. Let me know