Unicom's 4G network has become 3G, but it can't connect to the Internet, so short messages can't be sent or sent, but others can't receive them. It's no use changing cards. How to solve it?

If your mobile phone can't surf the Internet or send short messages normally, please check the following:

1. If you don't restart your phone after upgrading to the 4G package, you can't use the Internet function normally;

2. Confirm whether there is a network. I suggest you use it in a place with strong signal.

3. Check whether there is any phone bill in the account. If the balance is insufficient, it needs to be recharged before it can be used;

4. Confirm whether the parameters of the mobile phone have been set;

5. Check whether the USIM card is inserted. If it's plugged in and still doesn't work, I suggest you go to the business hall to check whether the USIM card is faulty or not.

6. Check whether there is anything wrong with the mobile phone. It is suggested that you can change your mobile phone for testing.

The above situation has not been solved, you can contact the local manual customer service to handle it.