Be Awared that beta EPiServer Forms (0.21 version) crashes in episerver edit mode if no sites were configured previously.

Have spent several hours with this issue.

An exception of type 'Newtonsoft.Json.JsonSerializationException' occurred in Newtonsoft.Json.dll but was not handled in user code

Additional information: Error getting value from 'ExportingUrl' on 'EPiServer.Forms.FormsModuleViewModel'.

It happens because it tries to do following

private string ResolveUrlFromRoute(string route)
{
route = ModuleHelper.ToResource(route);
string absolutePath = SiteDefinition.Current.SiteUrl.AbsolutePath;
if (!string.IsNullOrEmpty(absolutePath.TrimStart('/')))
route = route.Replace(absolutePath, string.Empty);
return UriSupport.Combine(SiteDefinition.Current.SiteUrl.ToString(), route);
}