Issues with the senders server
If your correspondent’s email server is overloaded or has a configuration problem, or a ‘relay’ server they make use of has a problem, then this can cause emails they send you to be delayed.
How to fix:
- To be sure about the reason for the delay, review the email headers for an email which has been delayed. The headers must come from the email in your email client – forwarding the email for someone else to diagnose won’t work.