Why is my OpenApi file being marked as invalid?

Currently working on a test project with Readme for the first time and wanted to try and bring over my Postman collection. I went through the process of creating an OpenApi file with my Postman collection but when I upload it to Readme I get an error stating:

I'm not sure what the issue is here as this doesn't seem to match the actual file? Line 1 in the input file doesn't have a fourth position from what I can tell but maybe I'm missing something as this is my first time trying to utilize this.