On our side, Colin set the "stay logged in" time to something VERY long, many years... so our server will only log you out when it gets rebooted, which happens whenever they have problems with it; that only happens every month or so. I know that it's really rare for me to have to log in (even though I'm an admin, there is nothing special about my account in terms of staying logged in).
So in short... something is happening on your end. It could be a browser setting, or it could be your internet provider doing something. Unfortunately I am bad at troubleshooting those things especially not being there in person.
When making a long post, I recommend typing it in Notepad or some other program, then copy-and-paste it into the box here. That way if the posting fails, you can just try again without retyping everything.
Another way is that you can temporarily save your text without using Notepad. When you're still in the reply box, before you hit Submit, press CTRL-A and then CTRL-C. This selects all, then copies it to your computer's memory. Then hit Submit. If the post fails, try to reply again, and press CTRL-V to paste your text into the reply box.
I learned these tricks on OTHER sites; this problem is common to all web-based forums, not just ours.
(Note: the "save" button when making a reply DOES work as designed, but it won't solve the problem of a dropped connection.)
Dennis
1980 Monza Coupe--collector of cob webs and kids' toys
2006 Honda Odyssey--daily driver
2011 Toyota Sienna--wife's
1995 Dodge Ram--for creating oil spots on the street