Why can't the oppo mobile phone receive the postal pick-up code?

We have sorted out the following methods to deal with the failure of sending and receiving short messages on OPPO mobile phones: 1. Confirm whether the mobile phone card is in arrears and ensure that the phone bill balance is sufficient. 2. I suggest you restart your mobile phone or switch flight mode to search the network again to see if it can be restored. 3. Correct the number of the information center. Check whether the phone information center number is correct first (please consult the operator to confirm the information center number). 4. Confirm whether the functions such as harassment interception/blacklist/information interception are turned on, and suggest turning them off. 5. Compare and observe the changes of SIM card and different time periods, and investigate the cause of the problem. If the above methods fail to solve your problem, please bring the relevant purchase voucher to the nearest OPPO customer service center for testing and handling. This answer applies to all OPPO models.