Trouble simply posting comments (end user)

I am having trouble posting comments using the FB plugin to a blog I read, even when logged in to Facebook. Plenty of people are posting there and i used to be able to then i no longer could. Symptom: post looks like it was made, then i see the same post grayed out at top of the post. After hitting post it looks like it took, then when i go back to the page, the post does not appear. Refreshing does not make it appear. Nor does going to another page and back to the page where the post should display.