Error connecting to server

Problem

Error while adding an account, or while synchronising.

Error message

        A connection with the server could not be established

        System.Exception: The text associated with this error code could not be found.
    

Possible causes

This error can have multiple causes. Here are some possible causes. It's possible this list is not exhausting.

• An add blocker that is installed in your browser is blocking traffic from/to OneCalendar. This can be caused by a recent update of the add blocker.
• A Windows update has caused traffic from/to OneCalendar to be blocked.
• The VPN connection is blocking traffic from/to OneCalendar. This can be caused by a recent update of the VPN client.