Unable to post a reply

Unable to Post a Reply. I have been trying to reply to those who responded to my last post. When I click on ‘Post’ I get a message in red informing me that my message cannot be saved, and to try again in a few minutes. Also, above the window in which I have typed my reply, there is a message telling me my session has timed out. I’m not a speeding typist, but I doubt I took more than 5-10 mins to enter my message. What’s going on? I would like to respond to those who offered suggestions.