InvalidOperationException: Can't use schemaId for type The same schemaId is already used for type

 After adding new bean to project I got below error during startup

13:44:19:254 ---> System.InvalidOperationException: Can't use schemaId "$Employee" for type "$staff.Employee". The same schemaId is already used for type "$test.Employee" 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SchemaRepository.RegisterType(Type type, String schemaId) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateReferencedSchema(DataContract dataContract, SchemaRepository schemaRepository, Func`1 definitionFactory) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateConcreteSchema(DataContract dataContract, SchemaRepository schemaRepository) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateSchemaForType(Type modelType, SchemaRepository schemaRepository) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateSchema(Type modelType, SchemaRepository schemaRepository, MemberInfo memberInfo, ParameterInfo parameterInfo) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.CreateArraySchema(DataContract dataContract, SchemaRepository schemaRepository) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.<>c__DisplayClass10_0.b__1() 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateConcreteSchema(DataContract dataContract, SchemaRepository schemaRepository) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateSchemaForParameter(Type modelType, SchemaRepository schemaRepository, ParameterInfo parameterInfo) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SchemaGenerator.GenerateSchema(Type modelType, SchemaRepository schemaRepository, MemberInfo memberInfo, ParameterInfo parameterInfo) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateSchema(Type type, SchemaRepository schemaRepository, PropertyInfo propertyInfo, ParameterInfo parameterInfo) 13:44:19:254 --- End of inner exception stack trace --- 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateSchema(Type type, SchemaRepository schemaRepository, PropertyInfo propertyInfo, ParameterInfo parameterInfo) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateRequestBodyFromBodyParameter(ApiDescription apiDescription, SchemaRepository schemaRepository, ApiParameterDescription bodyParameter) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateRequestBody(ApiDescription apiDescription, SchemaRepository schemaRepository) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateOperation(ApiDescription apiDescription, SchemaRepository schemaRepository) 13:44:19:254 --- End of inner exception stack trace --- 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateOperation(ApiDescription apiDescription, SchemaRepository schemaRepository) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateOperations(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GeneratePaths(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository) 13:44:19:254 at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GetSwagger(String documentName, String host, String basePath) 13:44:19:254 at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider) 13:44:19:254 at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context) 13:44:19:254 at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

Solution : 

The only change needed is in your Startup.cs inside the method ConfigureServices.

You should add the following:

services.AddSwaggerGen(options =>

{

    options.CustomSchemaIds(type => type.ToString());

});