We are sorry to hear that you have such issue. We checked and fixed your project, now it works fine for us. The reason of the issue was that you specified wrong user name in your HomeController. By default (anonym user) GroupDocs.Annotation uses email@example.com user name. To set different user name for annotation you should use Get parameter “un”. For example your URL could be – http://localhost:7015/?un=testuser. In that case user name will be “testuser”
Please download fixed project here - https://drive.google.com/file/d/0Bw7FRVMOzHsUNE5la0MyS1N0cFU/edit?usp=sharing.
If you will have more questions please feel free to contact us.