There are too many emails in the mailbox to receive short messages.

The mailbox of 126 has been used for 10 years, and there are too many emails to be received. You should do this: too much junk in the received mail takes up disk memory, so you can receive it by cleaning the mailbox. In the face of receiving too much spam, you can set up spam interception, which can reduce the memory occupied by receiving a large number of spam.