@johnrj1226
It may be related to sign-in credentials expiring or needing to be entered again.
If it is like the issue I have run into, you may be able to get around that by opening a community page in another browser tab and reloading the page or signing in using that other page. In most cases, I do not actually need to actually sign in with credentials -- clicking on the sign in link is enough. Once your username appears in place of the "sign in" link, go back to your original page and copy your text (if you were composing a response) and hit refresh or hit the back page (if you had already tried to submit a response). You may have the opportunity to reload a saved version of your response -- check to see if it is up to date or if you need to add anything to it, and then just submit it again.
Check your account site preferences -- there is a check box at the bottom to keep you signed in to the community boards. Make sure that is checked and hit "apply".
