The "All Sharer AeroFS Clients Are Offline" message means that none of the devices belonging to the person who created the secure link are online.
The following conditions need to be met in order to access files from the link.
- API Access must enabled on the sharer's AeroFS Desktop Client or Team Server.
- At least one of the sharer's AeroFS Desktop Clients. Alternatively, the sharer's Team Server must be running.
Once you have ensured that the sharer has met conditions 1 and 2, click on the shared link again.