When i was a GATSBY Build, i get 2 errors

This is my Gatsby Blog GitHub Link

When i work build i get 2 errors.

  1. The field "Mdx.excerpt." was explicitly defined as non-nullable via the schema customization API (by yourself or a plugin/theme). This means that this field is not optional and you have to define a value. If this is not your desired behavior and you defined the schema yourself, go to "createTypes" in gatsby-node.js. If you're using a plugin/theme, you can learn more here on how to fix field types:

  1. An error occurred during parallel query running.

When i was get build, gatsby give me some suggestions for my errors in this terminal.

Suggestion For first error

Suggestion for Second Error

How can i these fix.?

For the run my project, in this terminal

First step: npm install

Second Step: npm run dev