Good welfare tips. What's wrong with the postal service?

This situation is due to mail delay or wrong address.

1, mail delay: the mail may be delayed on the way, resulting in the recipient not receiving the mail on time. This may be caused by weather, traffic congestion or internal problems in the postal system.

2. Wrong address: If the address provided by the sender or the recipient is wrong, the mail may not be delivered successfully. This may be caused by input error, incomplete or invalid address, etc.