I'm having real problems this morning viewing and replying to mail via the webmail.
When I log in, the start page sometimes lists the first few messages in my inbox and sometimes says I have none.
Then when I click on the inbox, sometimes I'm getting the full list, sometimes it tells me I have no messages.
On the occasions when it successfully lists my messages, when I try to reply to messages, it opens a reply window but there's nothing in it and no email address in the 'To' field. This happens even when I open the message in a new window (successfully) before replying.
There doesn't appear to be any sequence of actions that can consistently either reproduce or avoid this, unfortunately.