If You’ve ever received the dreaded exclamation mark when trying to send an SMS on an iPhone (which is usually accompanied by an error such as “Error Sending Message” you should try checking your Message Center Number is correct for your mobile carrier.

I have a Dell Mini 9 Laptop with built in HSDPA modem using Vodafone (AU) but also an iPhone 3GS with Optus. While trying to diagnose an issue I switched sims, and somehow my iPhone kept the Message Centre Number for Vodafone – Even while my Optus sim was present in my iPhone.

I tried reseting the Network settings as suggested on some sites, and even resorted to Restoring my phone (effectively wiping it) however this didnt fix the issue.

The following shows how the issue was resolved.

Step 1 – Check the Message Centre Number

Go into the phone app, and choose the keypad. Enter the following:

*#5005*7672#

and hit call. You will receive a message such as:

Setting Interrogation Succeeded
Service Center Address
+61415011501

The message above indicates the MCN is for Vodafone when it should be Optus.

Step 2 – Change the MCN

To change the MCN you enter the following into your keypad as done previously:

**5005*7672*+xxxxxxxxxxxxx#

Replace the x ‘s with the MCN for your mobile provider (See resources below for a world wide list). You can enter the + symbol by holding down the 0 button.

In my case, I was changing from vodafone to optus. Optus advises on their support page that their MCN is +61411990001 , so I would key in the following:

**5005*7672*+61411990001#

Followed by the call key.

You should now receive a message such as:

Setting Succeeded Service
Center Address
No Address

You can now try send an SMS. If you continue to have issues, please repeat step 1 to confirm your MCN has been entered correctly. Failing this I’d advise you call your mobile provider to run through other options.

Further Resources:

SMS Message Server Worldwide List (MCN List)

Optus SMS Troubleshooting

Feedback:

Please leave a comment if this resolved your issue, or if you have any further solutions to this problem. If you are having similar issues and have found a solution, please post the solution you have found.