I've lost the ability to edit any pages on one of my DNN sites. When I attempt to edit the page a popup window quickly appears and then goes away. There is nothing in the event viewer.

My other site on the same computer still works OK, so its not a browser issue. Any suggestions on resolving this would be appreciated.

Thanks Great Suggestion.

I reinstalled everything and everything was OK for a while. During my module development the issue re-occured. Its seems that my host account no longer has permissions to Toggle User mode. I uninstalled the module I'm developing, its test page as well as any of my .dlls in the DNN bin folder but the problem will not resolve itself. Any suggestions would be greatly appreciated. Here's the fiddler dump.

POST /DesktopModules/internalservices/API/controlbar/ToggleUserMode HTTP/1.1
Accept: */*
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
ModuleId: undefined
TabId: 56
RequestVerificationToken: DFBC3lqSUaFEl1Jvkkd2H1ZaMS2b90TbWvQm-HdMc4Eim44TTEgJSXI94wT3eOTJjl4YtsgwMpuDG4iYtWq-puWFAMBsPWzvwf1fo09oCE5-uOL5tMUrrb3nznQEN6316qqbLw2
X-Requested-With: XMLHttpRequest
Referer: http://www.stackfish.com/
Accept-Language: en-us
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)
Host: www.stackfish.com
Content-Length: 13
Connection: Keep-Alive
Pragma: no-cache
Cookie: .ASPXANONYMOUS=eSvnO4OOzgEkAAAAMjc5YTZjNTAtMjg5MC00MjY1LTgxZTctNGM5MzE2MGJkMmE10; ASP.NET_SessionId=tug3g23cbcqyvbyvgtpfkl5k; language=en-US; authentication=DNN; .DOTNETNUKE=DE04C01F618759E97E490B2302F5EA013A301F7D77D76CE4C2E79BA1C59C77877DAE9E8F74171A4E236E62D857FB2C515E6235D00FBAB6821C5CFF4677A5AE799C978980EE0B4770C78F3957C19DEFC0A4F540C5C541002C13B38BB449744B7D998BC8025493BF62CE0410EE; LastPageId=0:56; __RequestVerificationToken=2DGcfFlZ33aW7e4_V9thWgcz_5QUsQ-nv01cDdezUmfJO_zMmYtQhrtgsX75vgQbfztJjItmXsi4P09WFgrwt3Nkhm2CYONyBAuyjt4IA8gt42J01Tet5suTzbc1; StayInEditMode=NO

HTTP/1.1 401 Unauthorized
Cache-Control: no-cache
Pragma: no-cache
Content-Type: application/json; charset=utf-8
Expires: -1
Server: Microsoft-IIS/7.5
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Sun, 26 May 2013 10:06:19 GMT
Content-Length: 45