Many times, I saw this error in asp.net log files, when I used asp.net reportviewer for render SSRS reports on asp.net page.
The attempt to connect to the report server failed. Check your connection information and that the report server is a compatible version.
Debug Info: RepReportViewer::Page_Load-Page could not be loaded: Error occured
StackTrace: at Microsoft.Reporting.WebForms.Internal.Soap.ReportingServices2005.Execution.RSExecutionConnection.ProxyMethodInvocation.Execute[TReturn](RSExecutionConnection connection, ProxyMethod`1 initialMethod, ProxyMethod`1 retryMethod)
at Microsoft.Reporting.WebForms.ServerReport.EnsureExecutionSession()
at Microsoft.Reporting.WebForms.ServerReport.GetParameters()
at repreportviewer.Page_Load(Object sender, EventArgs e) in C:\www\clinics\View.aspx.vb:line 108
InnerException:Client found response content type of '', but expected 'text/xml'.
The request failed with an empty response.
In order to solve the problem, I opened the rssrvpolicy.config reporting services configuration file in the ReportServer virtual directory of the IIS where the report server exists. That is the C:\Program Files\Microsoft SQL Server\MSRS11.MSSQLSERVER\Reporting Services\ReportServer folder with a default installation.
I updated the following CodeGroup block permission set from Nothing
<CodeGroup
class="FirstMatchCodeGroup"
version="1"
PermissionSetName="Nothing">
to FullTrust in order to let the application access the assemblies successfully.
<CodeGroup
class="FirstMatchCodeGroup"
version="1"
PermissionSetName="FullTrust">
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