Can not retrieve the attachment in PO for specific user

Hi, my specific user failed to open attachment in citrix machine (thin client)

1. specific user hits this error using citrix machine 2. happen in fixasset PO printout - by the time you clicked save and exit, it did not prompt error 3. When open back that specific  PO for the attachment , it did not show the 140076CQ proof attachment in the attachment window Pls refer attached for the actual screen many thanks