Apollo-Kotlin: After creating schema.graphql android studio is showing Unsupported token `!` error

Steps that I made so far.

• Downloaded an install the graphql plugin to execute the queries internally.

• Created this config file for executing local queries for the expected behavior.

• Which is working fine with performing general query. But with this config I am getting following error while building project and run it on a device.

   Failed to parse GraphQL file E:\...\src\main\graphql\schema.graphql (9:13) Unsupported token `!`
  

FYI, I have already gone through this ticket from apollo-kotlin github page. Doesn't resolve my problem or I don't understand the solution there.

For now, By deleting the E:\...\src\main\graphql\schema.graphql file, the project builds and runs just fine.

If anyone has more idea on this, let me know and I will update if I find anything else as well. Thanks