[Plugin: Official Topspin WordPress Plugin] API Authorization Fail. Topspin Admin couldn't solv

Error 401 Unauthorized request. Please check your API username and key keeps appearing despite I’ve checked and verified many times.

Have also approached Topspin for support, they looked at my wp-admin and couldn’t figure out the problem either. There’s no problem with my API user and key.

http://ww.wp.xz.cn/extend/plugins/official-topspin-wordpress-plugin/