SQL dependency error

I'm using sql dependeny to see the changes in db table and push notification to users(signalR):

https://msdn.microsoft.com/en-us/library/62xk7953%28v=vs.110%29.aspx?f=255&MSPPError=-2147217396

This sql dependency works with service broker queue.

I have install web site on my IIS 8 (beside default one) and test it. Everything worked with test domain and test database(copy of production). Then I set up domain name which previously show to default site to show on new web site and in config set connection to production database and everything stop working. On sql server I got hundreds of uncommitted transactions, on web site i get javascript errors like my library is not defined ("Ext is not defined"),.... From event log i get this error:

3005 
   An unhandled exception has occurred. 
   15.9.2015 17:39:14 
   15.9.2015 15:39:14 
   03a0709e2a684122a9fa13e47672f744 
   1 
   1 
   0 
   /LM/W3SVC/1/ROOT-101-130868051546780412 
   / 
   C:\APP\myApp\ 
   MYSQLSEREVR 
   7016 
   w3wp.exe 
   MYDOMAIN\user.name
   InvalidOperationException 
   Failed to map the path '/'. at System.Web.Configuration.ProcessHostConfigUtils.MapPathActual(String siteName, VirtualPath path) at System.Web.Configuration.ProcessHostMapPath.MapPathCaching(String siteID, VirtualPath path) at System.Web.Configuration.ProcessHostMapPath.System.Web.Configuration.IConfigMapPath2.MapPath(String siteID, VirtualPath path) at System.Web.Configuration.WebConfigurationHost.InitForConfiguration(String& locationSubPath, String& configPath, String& locationConfigPath, IInternalConfigRoot configRoot, Object[] hostInitConfigurationParams) at System.Configuration.Configuration..ctor(String locationSubPath, Type typeConfigHost, Object[] hostInitConfigurationParams) at System.Configuration.Internal.InternalConfigConfigurationFactory.System.Configuration.Internal.IInternalConfigConfigurationFactory.Create(Type typeConfigHost, Object[] hostInitConfigurationParams) at System.Web.Configuration.WebConfigurationHost.OpenConfiguration(WebLevel webLevel, ConfigurationFileMap fileMap, VirtualPath path, String site, String locationSubPath, String server, String userName, String password, IntPtr tokenHandle) at System.Web.Configuration.WebConfigurationManager.OpenWebConfigurationImpl(WebLevel webLevel, ConfigurationFileMap fileMap, String path, String site, String locationSubPath, String server, String userName, String password, IntPtr userToken) at System.Web.Hosting.ApplicationManager.CreateAppDomainWithHostingEnvironment(String appId, IApplicationHost appHost, HostingEnvironmentParameters hostingParameters) at System.Web.HttpRuntime.HostingInit(HostingEnvironmentFlags hostingFlags, PolicyLevel policyLevel, Exception appDomainCreationException)  
   http://myApp/signalr/negotiate?clientProtocol=1.5&connectionToken=Wd8y17bNkn7lYC/KWr612d/gbcIu4Mv/oPdtNkSddbsigvJiL3XMshOE5p8GzbybGp6yKSijgF5x03OWy+oZoiJxdXIyG9rmzIBnvonbJxmBhEBWOJYVao+HWRh3CctsQr1HmYsVJMCpDOZmuaM1lw==&connectionData=[{"name":"stockalignmenthub"}]&_=1442331554547 
   /signalr/negotiate 
   10.50.84.213 
   False 
   MYDOMAIN\user.name 
   49 
   MYDOMAIN\user.name
   False 
   at System.Web.HttpRuntime.HostingInit(HostingEnvironmentFlags hostingFlags, PolicyLevel policyLevel, Exception appDomainCreationException)  

Any idea what is could be?