@Mike1052 Oh, that's just a glitchy thing that happens on this forum. For some reason, it isn't considered a bug.
If you take a long time to compose a post, either because it's long, or you got up to make a sandwich, it "times out", then you get those error messages.
What those of us who are used to it do is to copy the text of your post before hitting Reply, so if it disappears into cyberspace, you can just quickly paste it back into a new response box and hit Reply again.