Iphone can't receive mail from Exchange - reads No Mail although account active

IPhone 5 - successfully connected to the Exchange server during the setup of my Exchange email account on device. All Mail settings match other users who successfully connect and get mail, except of course the specific user info for me. Password is correct.

Someone else setup their email successfully on this device and received email. However I cannot receive email on the device - it reads 'No Mail' in the mailbox. Account active, mailbox accessible from other Windows based devices and there is mail in the mailbox. Sent a new mail to the address and nothing arrived on IPhone.

Something is blocking the delivery of mail for my user to Apple devices. Same problem on my IPAD.

Any ideas on where the blocking may occur?