Duplicate e-mails in Outlook

[wrxnfx]

If this has been asked before, I apologize in advance as I didn't see anything after using the search. Also, haven't found answers after searching the web. This is in regard to my mother-in-law's iPhone 4G on Verizon. After having her e-mails pushed to her iPhone, she gets duplicate incoming e-mails on Outlook even though she only sees one on her iPhone. Anyone know what might be causing this and if there is a way of preventing the duplicates? Any suggestions or advice would be appreciated.

 

[takeshi]

Outlook doesn't really help much. What type of email account is it? Outlook supports a number of different types of email accounts.

 

[wrxnfx]

It's with Hawaiian Telcom so not too much info available.