outlook error on specific email address

Hi, one of our users started having an issue in outlook where she receives an email from someone with an aol address and when she tries to open it she cant and if she can she cant scroll thru the email and it only happens from this particular email address.  She tested the email by forwarding it to her gmail account and she could view it no problem.  The error that outlook produced was something like "Contacting od:x.MA3.1472057957@aol.com and it has a green progress bar like its trying to complete a task but just hangs.  Any ideas?  Thanks.