Iphone email receives headers only

[DataDevPro]

I had tried several different ways to set up my email account on my iphone 4 using the different options (IMAP and POP) before getting it right to allow me to both receive and send from my iphone. However, I am still plagued with about half of my received email containing only the header and with the nefarious "This message has not been downloaded from the server." It also has a message "This message is only partly downloaded" with a button to download the remainder of the message, only the button never works.

How can I configure my iphone to receieve complete emails and/or get it to download the missing portions?