You have changed the available content files in EndNote Web but this change is not reflected in the accounts of the other users at your University/institution.
The user has probably logged on whilst being associated (via IP recognition or through a proxy) with another University/institution's account and so become accidentally tied to it, typically MIMAS/University of Manchester. EndNote Web's administration systems only support being associated to one account and as a result the changes the administrator makes would be applied to the incorrect account.
The user should log out and back in whilst authenticated from the correct University/institution and they should be able to make the correct changes to the content file availability. If this fails, contact firstname.lastname@example.org - we'll pass this to the support channels at ThomsomReuters who can remove the incorrect MIMAS link.