Title and description tags not saved with Yoast SEO plugin

Hi, I have a problem, I can't save title and description tags with Yoast SEO plugin on my site made with Gridalicious free theme, which I really love. I've found some info here, do you think this could be the problem? https://kb.yoast.com/kb/the-seo-title-output-for-the-plugin-doesnt-work-as-expected/ Thanks Francesco