Why can't I send and receive SMS after upgrading my iphone6 Unicom card to 4g?

This may be caused by the unsuccessful number setting of your SMS center. You can reset the SMS center number.

The steps to set the number of the IPHONE SMS center are as follows:

Inquiry method on IPHONE: dial *#5005*7672# with iPhone.

Setting method: dial * 5005 * 7672 *+86 "SIM card home SMS center number" with iPhone #

Delete method: dial ##5005*7672# with iPhone.

Note: The set SMS center number is generally similar to the mobile phone number after +86. When setting the number of the SMS center, please insert and unplug the SIM card again. It is suggested to delete the SMS center number before resetting it, that's all.

Please contact Unicom customer service 100 10 for the specific SMS center number. If you still can't send and receive SMS after setting, it is suggested that you can change your mobile phone to test or call 100 10 to check whether the SMS function of this number is turned on normally.