I created a DNN Portal, and after I try to login / logout I get the same error.

The site was running fine until a couple of days ago this error started showing up.
Nothing was changed. The home page has some standard out-of-the-box DNN modules (announcements, HTML, etc) and some custom built modules (that have not been changed and that have been working for months).

The architecture is composed by 2 machines, one for front-end and one for SQL.
We are using SQL Server 2008, and the frontend is using Windows Server 2008.

We are also using Cache (Heavy Caching) to increase site performance.

The login control is the DNN default. We have not modified it in terms of functionality.
We have simply changed it's layout and design by using customized CSS, but in terms of functionality nothing has been done.


In the Event Log I get the following entry:




AssemblyVersion: 5.4.2
PortalID: 1
PortalName: #######
UserID: #
UserName: #
ActiveTabID: 62
ActiveTabName: #######
RawURL: /default.aspx
AbsoluteURL: /default.aspx
AbsoluteURLReferrer: #######
UserAgent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; Media Center PC 6.0; .NET4.0C; Tablet PC 2.0)
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: 5806c7ef-fa06-4292-aabd-a3b85bc1371e
InnerException: Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request.
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Web.UI.Control.LoadViewStateRecursive
StackTrace:
Message: DotNetNuke.Services.Exceptions.PageLoadException: Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request. ---> System.Web.HttpException: Failed to load viewstate. The control tree into which viewstate is being loaded must match the control tree that was used to save viewstate during the previous request. For example, when adding controls dynamically, the controls added during a post-back must match the type and position of the controls added during the initial request. at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Control.LoadChildViewStateByIndex(ArrayList childState) at System.Web.UI.Control.LoadViewStateRecursive(Object savedState) at System.Web.UI.Page.LoadAllState() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) --- End of inner exception stack trace ---
Source:
Server Name: #######




Any help is welcome.
Right now I don't know why this is happening, and I'm stuck in the solution, because I don't even know where this is happening, how and why.

I do not think this has anything to do with out modules, you may want to contact your hosting provider about this issue.

I noticed you have also posted this on the DotNetNuke.com forums.

A suggestion I found there was:

1) Clear browser cache
2) Clear browser cookies
3) Restart IIS (Now test)
4) Host/Extensions: If LiveID and OpenID Authentication is there disable it (Now test).
5) Restart IIS (Now test).
6) Host/Host Settings - Try playing with your page state persistance and module caching methods.