If you've recently upgraded an older DNN site to DNN 9.2, and experienced a login problem, resulting in an error that says
Specified argument was out of the range of valid values.
Parameter name: slidingExpiration
You're probably frustrated that you can't login and use your DNN site. If you're lucky, you still have a browser where you have a user logged in and able to access the site (I was lucky).
I spent quite a bit of time trying to track down the problem and ultimately resorted in simply going line by line through the web.config file of my site and a clean DNN 9.2 instance to see what the differences were. I had a LOT of differences, the site I was having problems with has been running DNN for 10+ years, so it has gone through countless upgrades.
Ultimately this all came down to a change I made to the web.config years ago to allow for a user to remain logged in.
<forms name=".DOTNETNUKE" protection="All" timeout="100000" cookieless="UseCookies" />
The problem is that timeout value, I had it set at 100k, while the default in DNN 9.2 is 60. I changed that value to 60, uploaded the web.config to my site, and was able to successfully login. I then changed it to 10000 instead of 60, and I am still able to login and access the site.
Hopefully this blog post will save you some headache!
Here's a thread discussing the issue in the forums. http://www.dnnsoftware.com/forums/forumid/200/postid/541946/scope/posts#541946