I have created an application for testing write-access APIs. After registration, I can successfully retrieve an access token by hitting the URL:

https://stackexchange.com/oauth/dialog?client_id=3973&scope=write_access&redirect_uri=stackexchange.com/oauth/login_success

But when I tried to post a question using /questions/add, it shows an error:

"We are no longer accepting questions from this account."

What could be the reason ? I don't think I have been restricted from posting questions as I could post questions manually. What is the solution?