I post many comments through out this forum and it is most definitely not "all over filemaker forums" here though I can't speak for other digital communities that support Filemaker development. I also support a FileMaker Database made up of over 100 files with a large user base using Filemaker 13 and FileMaker 13 server. What you describe has not happened once in this system that we can clearly identify as a case of simply accessing a particular layout.
Thank you for your post.
Error 701 is "Admin Server process has terminated abnormally". When you go into Admin Console, are all processes running? Check the Web Publishing engine.
Are users still able to access the hosted files?
What version of FileMaker Server are you running? What version of FileMaker Pro are the clients running?
What appears in the Event log prior to the error? Access log?
Any other information you can provide may be helpful in determining the cause.