This is actually a problem I faced myself, and discovered the answer to, but it would help a lot of people with the same issue.

Background: I was reviewing the Nokia E72 when I realised that it could not connect to data (internet, email etc) even though the settings are all correct. I also recalled that I had the same issue with DK’s N97 when I was playing with it back then.  It would say something like “Connection not allowed”. The same SIM card had no issues in the past when I reviewed other smart phones. Then I realised that this all started ever since I got my iPhone.

Question: Ever since I got my iPhone from Singtel, I can no longer use my SIM card on another device to connect to the internet. What’s going on? What can I do?

Answer: That is because for some reason, connection restrictions were put into your Singtel SIM card. Why they did that and was it right for them to do it is a complete different issue and discussion altogether. Let us just focus on getting that fixed first.

If you’re on a modern Nokia S60 device, when you go to Settings > Connection > APN control, an error message might appear saying “connection restrictions are active”. Selecting “Options > Deactivate Restrictions” will ask for a PIN2 code.

Give Singtel customer service a call (1626). Go to the Technical Support option to speak to someone. Wait. And wait. And wait some more. (It’s a phone hotline, they’re all slow).

Tell the officer that you are very certain that your settings are correct (be sure they are in the first place, compare them with your iPhone’s data settings), and tell him that you see the “Connection restrictions are active” message and when you try to deactivate it it will ask for a PIN2 code. He will give you a few PIN2 codes that most likely won’t work, and on the 3rd attempt the SIM card will lock itself and ask for a PUK2 code. Don’t worry, he has the PUK2 code (check with him before hand first). Once you enter the long PUK2 code he provides, set a new PIN2 code and proceed to deactivate those restrictions. All done!

Now, obviously the steps sound quite specific to S60 phones, but if you face the same issue on a non S60 device, navigate around the device’s connection settings menus until you reach a place that causes a similar message to appear. If not, just call the customer hotline and tell them that you’re sure the settings are correct and that you have an iPhone from Singtel.

Hope this helps!