Error 404

If you had left the page for a long time you may have timed out.

I was not timed out because I had just logged in to make changes to an agenda. As I recall, I selected Manage Meeting → Edit Meeting → Manage Agenda, and then realized I was on the wrong path, so I used the browser’s Back arrow.I was able to use the Back arrow successfully several times until I encountered the error.
So I returned to the Manage Meeting page and successfuly clicked the dashboard link.

Everything seems to work find today. 

next time that happened do a screen shot and upload it to the support forum so we can see what happened.

Will do.
I included a pdf when I posted this question originally.  Was what I included in the upload not detailed enough?

copy and pasting the URL makes it easy for us to click  and go directly to the page with the issue.
A pdf we have to try and read the url and  then retype it.

Ah. Understood.