Unhandled exception: System.ArgumentException: The source text mustn't be null or empty. (Parameter 'sourceText')

[Fettah]

I am integrating my graphql backend with this amazing tool but I am getting this error in AzueDevops. any idea ?

Unhandled exception: System.ArgumentException: The source text mustn't be null or empty. (Parameter 'sourceText')
   at HotChocolate.Language.Utf8GraphQLParser.Parse(String sourceText, ParserOptions options)
   at HotChocolate.Language.Utf8GraphQLParser.Parse(String sourceText)
   at SchemaCompare.SchemaComparer.DetectBreakingChanges(String oldSchema, String newSchema) in C:\github\GraphQlBreakingSchemaChangeDetector\src\SchemaCompare\SchemaComparer.cs:line 10
   at AzureDevops.AdoSchemaComparer.CreateCommentsForBreakingChanges(String file) in C:\github\GraphQlBreakingSchemaChangeDetector\src\Integration\AzureDevops\AdoSchemaComparer.cs:line 47
   at AzureDevops.AdoSchemaComparer.ReportBreakingChangesInPr(String file) in C:\github\GraphQlBreakingSchemaChangeDetector\src\Integration\AzureDevops\AdoSchemaComparer.cs:line 23
   at Cli.PrCommand.<>c.<<Create>b__0_1>d.MoveNext() in C:\github\GraphQlBreakingSchemaChangeDetector\src\Cli\PrCommand.cs:line 38
--- End of stack trace from previous location ---
   at System.CommandLine.Invocation.AnonymousCommandHandler.InvokeAsync(InvocationContext context)
   at System.CommandLine.Invocation.InvocationPipeline.<>c__DisplayClass4_0.<<BuildInvocationChain>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at System.CommandLine.Builder.CommandLineBuilderExtensions.<>c__DisplayClass18_0.<<UseParseErrorReporting>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at System.CommandLine.Builder.CommandLineBuilderExtensions.<>c__DisplayClass13_0.<<UseHelp>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at System.CommandLine.Builder.CommandLineBuilderExtensions.<>c__DisplayClass22_0.<<UseVersionOption>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at System.CommandLine.Builder.CommandLineBuilderExtensions.<>c__DisplayClass20_0.<<UseTypoCorrections>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at System.CommandLine.Builder.CommandLineBuilderExtensions.<>c.<<UseSuggestDirective>b__19_0>d.MoveNext()
--- End of stack trace from previous location ---
   at System.CommandLine.Builder.CommandLineBuilderExtensions.<>c__DisplayClass17_0.<<UseParseDirective>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at System.CommandLine.Builder.CommandLineBuilderExtensions.<>c.<<RegisterWithDotnetSuggest>b__6_0>d.MoveNext()
--- End of stack trace from previous location ---
   at System.CommandLine.Builder.CommandLineBuilderExtensions.<>c__DisplayClass9_0.<<UseExceptionHandler>b__0>d.MoveNext()

Here is the code I am using:

stages:
  - stage: graphql_inspection_dotnet
    displayName: 'Graphql Inspection Dotnet'
    jobs:
      - job: graphql_inspection_job
        displayName: 'Graphql Inspection Dotnet'
        pool:
          vmImage: 'ubuntu-latest'
        steps:
          - task: UseDotNet@2
            inputs:
              version: '6.0.x'
              includePreviewVersions: false

          - checkout: self
            displayName: 'Checkout'
            clean: true
            persistCredentials: true

          - script: |
              dotnet tool install --tool-path . graphql-breaking-schema-change-detector
              cat ./apps/time-series-api/src/schema.gql
              ./breaking-change pr --file ./apps/time-series-api/src/schema.gql
            env:
              SYSTEM_ACCESSTOKEN: $(System.AccessToken)
            displayName: 'Run Breaking Change Detector'