Error when clients sends email to my Domain

1

Below is the error but I cannot send out to other domains.
reason for the problem:
5.4.7 - Delivery expired (message too old) ‘timeout’
Please help out

2

Hi,

This error is not specific. Are there no other errors?
Split your screen with webmail on one side and logs on the other and see what appears when you send.
Are you confident with your DNS? Do you have SPF entry?

Rgds.