Sorry, the problem is still there – WordPress and all plugins are updated to latest version. No more than 100 posts. The server has the right requirement.
I have followed your suggestions below – except (as I mentioned earlier) The “SEO Data” Button under SEO -> Tools says “Start SEO Data Optimization” and “NOT SEO Data” on my site. If this is the button you mean, it only gives the same error message: “Oopps something has gone wrong… etc” SO the Yoast Test Helper did not help in this case.
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– i. Install & activate the Yoast Test Helper plugin: https://www.ads-software.com/plugins/yoast-test-helper/
– ii. Go to Tools -> Yoast Test
– iii. Locate the Yoast SEO section and select the “Reset indexables tables & migrations” button
– iv. Click the “SEO Data” button in the SEO->Tools section.