Unable to reply

I recently submitted a question and received some really useful responses. However I can’t seem to be able to reply to individuals. When I select reply, a window opens, I then type my response/query. When I try to submit, the window turns red and I get a message saying that my session has closed, and to retry. I’m literally online for 5 minutes. When I log in again, retrieve the draft and submit, the same thing happens. I concerned that people will think that I don’t appreciate their suggestions.