“Error in required structured data element” was a Google Search Console error I received for my Squarespace website. I was able to resolve my own issue. Sorry if this doesn’t help you with your needs, or if this video is outdated several years from now.
The “error in required structured data element” error was resolved for me after I added a site logo in Squarespace. Also, just in case it helped, I converted my browser icon favicon from a PNG to an ICO file. I also sized it down to 16×16.
This error is annoying, but hopefully this video helped you. Leave a comment if you need more assistance, and commenters can work together to resolve this mess.