Yoast SEO Unavailable

HI, All of a sudden on all my sites I am getting Yoast SEO Unavailable (greyed out) the last week or so. Never had this issue before. Just completed a client’s website and it says this on the localhost. Other live clients are now getting it also. Before you say that you have to have content in there (as I have read from previous posts), of course it has text and content on the page… SEO on the page is still greyed out … something not quite right. I have some client sites on 4.6.1 and still greyed out, and was originally on localhost on 4.5.2 and not greyed out, was working. Now they are not. And as I mentioned my new client site just a 1 pager ready to go live has now gone to greyed out also. As I have always used this plugin, I am worried that Google is not going to pickup the text that is already in this plugin for the Search engines.

Please advise what is wrong urgently and how to fix it. I see from previous posts approx 4 months ago that there was no resolution. I hope there is now, as no-one can survive having this plugin not working properly for our websites ! Thx Kristin