Hi @grdspublishing,
I suspect there is something outside OJS that is preventing the OAI validation from working. If I look at your OAI page with a web browser, it works fine – but attempting to fetch it with another tool like wget results in a 403 Forbidden error. I suspect your web server is set up to deny requests depending on the user agent.
Regards,
Alec Smecher
Public Knowledge Project Team