Send/receive is not working


Hi All,
This morning 1 of my employee cant open her emails. She is receiving emails but mails are not showing in the reading pane. just getting this error when clicking on the mails: “This item cant be openned in the reading pane. The item has not been received from server”.
Also the send reading button in outlook is not working. I mean after clicking on this button, its not displaying other options.

So, which coniuration fotlook has been changed?
i checked but diid not found.