Invalid AMP : Got a mail from google search console

Hey team,

I had recently published one article and requested it to be indexed. I have amp settings checked for my blog.

Today I got this email saying

AMP issues detected on bhanusingh.in

To the owner of bhanusingh.in:

Search Console has identified that your site is affected by 1 AMP issues:

Top Warnings

Warnings are suggestions for improvement. Some warnings can affect your appearance on Search; some might be reclassified as errors in the future. The following warnings were found on your site:

Error in required structured data element

We recommend that you fix these issues when possible to enable the best experience and coverage in Google Search

The concerned blog is this one:

Although, my search console says "Valid with warnings".

How can I fix this issue?