In my case my image path had an extra forward slash, which worked fine in-browser, but wasn't picked up by Twitter. It was a one character error that was hard to spot.
E.g. check for this:
And change it to this:
I will allow myself to give an answer from the point of view of Google because I know a little with their documentation.
Duplicate content (regardless of location - in the metadata or in the main content of the web page) has the following negative result. The presence of duplicate content of the website does not allow Google to determine the relevant ...
These are all Open Graph protocol tags. The OG protocol is a metadata standard introduced by Facebook, and understood by many other online platforms like Twitter. While they won't help you with standard search engine indexing and ranking, your website will definitely benefit from them, because they tell Facebook and others how to interpret and display your ...
A robots meta tag with noindex will prevent Google from indexing a page. The meta tag takes precedence over:
Search console account: Registering for search console will show you additional information about how Google views your site, but it doesn't affect whether or not it is indexed.
Inclusion in an XML sitemap: Including a noindex page in a sitemap ...