In this article, we will talk about a few schema.org structured data markup errors that may show in Google Structured Data testing tools, and show you how to fix them if you are using our Schema Premium plugin for WordPress.
Schema Premium plugin has support for several schema.org markup types that you can easily implement in your WordPress website.
After setting up the plugin and enabling schema.org types on your website content, you may notice errors in Google Rich Results Testing Tool or in your Search Console.
Let’s go through the possible schema markup errors and see how to fix them.
Schema Structured Data Markup Errors
There are a few schema markup errors that you may notice, we will mention these errors below and show you a simple fix for each error.
1- A value for the mainEntity field is required
This error happen mainly if you are implementing schema.org FAQPage type on your content.
The reason on this error is that Questions and Answers are missing and needed to be entered manually in the Schema post meta.

Once you add Questions and Answers, the error should be cleared.
2- A value for the itemListElement field is required
If you are getting a value for the itemListElement field is required error, here is how to fix it within the Schema Premium plugin settings.

That error is mostly coming from Breadcrumbs markup, you need to go to Schemas settings to enable Show Homepage and set a Homepage Text for it to be fixed.
3- Image Size Smaller than Recommended Size
This is a popular error that is cause by uploading small dimension size image as a Featured Image in your Articles.

The simple fix is to always set a high quality images in your Articles per to Google’s guidelines. Upload images that has a width larger than 1200px and the error will go away.
4- The attribute publisher.itemtype has an invalid value
Google accepts only an Organization as a value for the publisher property. So, make sure you have it configured if you are seeing this error.

Other Schema Structured Data Errors?
We publish solutions and fixes for schema.org markup errors as reported from our customers.
Visit our Schema Premium documentation section for more details about Schema Structured Data errors to find a fix.
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