Why is my inbox not showing all emails?

[iMore Question]

This has just recently started and was fine prior to this download. My emails are only going back to Saturday and yet I have numerous that were showing prior to this update.

 

[MaxSmarties]

Is it an exchange account ?
In that case in the email settings you should have the option to sync emails from 1 day / 3 days / 1 week / 2 weeks / 1 month or unlimited