Can't open word file from C# application - COM exception HRESULT: 0x80010105 (RPC_E_SERVERFAULT)

I use this code inside my c# WPF application

            Application application = new Application();
            Document document = application.Documents.Open(fileName);

to get access to the text inside a word document (file created by Word 2016, format docx, Office 2016 installed on the machine). Unfortunately the second line always throws the exception: HRESULT: 0x80010105 (RPC_E_SERVERFAULT)

Please help... how can I resolve this. Thanks in advance.