The AMP plugin for WordPress makes it easy to support Accelerated Mobile Pages (AMP) on your blog, which is an open source initiative that aims to provide mobile optimized content that can load instantly everywhere.

However, there’s a common structured data validation Error found for AMP that many blog owner experience.

That Amp Error is “A value for the logo field is required.”

Follow the below steps to resolve “a value for the logo field is required.” AMP error

This can be easily fixed by adding a Site Icon in the Site Identity settings of your blog theme.

To access it, go to: Appearance > Customize.

Then click on Site Identity and Select a Site Icon from Media Library or upload a new Site Icon but make sure Icon is square and at least 512 pixels wide and tall.

Now Click on “Save & Publish” Button

After following above steps, go validate your AMP page using Google’s Structured Data Testing Tool and you can see in below image that error is gone.

Reference: https://raventools.com/blog/fix-common-amp-error-wordpress/