I'd been using Outlook on my computer for a couple of years when, seemingly all of a sudden, the Reply All stopped working. When I click on it, I get instead a message in the lower right part of the screen that says,

"The connection to Microsoft Exchange is unavailable. Outlook must be online or connected to complete this action."

Yet, I also see a "Connected to Microsoft Exchange" message on the status bar at the bottom of the Outlook screen. And I have no trouble doing a regular Reply. I do not experience this problem when I connect to my email using a webmail interface with my browser, so it seems to be a problem in my Outlook somewhere and not on the server. But I did check with the folks who run the server and all services are running properly and they have not experienced this issue with anyone else.

More recently, I've noticed that I get that message on some other features, too. This morning I tried to create an appointment and when I clicked the save button, I got the same message and it did not create the appointment.

Thank you for your help.