title: Failed to load API definition, Fetch error: undefined /swagger/v1/swagger.json
body: <p>this error occurred and I tries all the possible solutions on all sites and still not working
  I tries swaggeroperation
  I tries Route
  I tries HttpGet(&quot;List/{id}&quot;)
  nothing worked for me
  Error details are:</p>
  <pre><code>      An unhandled exception has occurred while executing the request.
        Swashbuckle.AspNetCore.SwaggerGen.SwaggerGeneratorException: Ambiguous HTTP method for action - MandobX.API.Controllers.ShipmentOperationsController.GetShipmentOperations (MandobX.API). Actions require an explicit HttpMethod binding for Swagger/OpenAPI 3.0
           at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GenerateOperations(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository)
           at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GeneratePaths(IEnumerable`1 apiDescriptions, SchemaRepository schemaRepository)
           at Swashbuckle.AspNetCore.SwaggerGen.SwaggerGenerator.GetSwagger(String documentName, String host, String basePath)
           at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
           at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context) 
  </code></pre>
  <p>My code:
  controllers Actions:</p>
  <pre><code>//Get lists of drivers, regions and packagges type to create shipment operation
          [Route(&quot;Init&quot;)]
          [HttpGet]
          public async Task&lt;IActionResult&gt; InitShipment()
          {
              ShipmentViewModel shipmentInitViewModel = new ShipmentViewModel
              {
                  Drivers = await _context.Drivers.Include(d =&gt; d.User).Include(d =&gt; d.Vehicle).ToListAsync(),
                  PackageTypes = await _context.PackageTypes.ToListAsync(),
                  Regions = await _context.Regions.ToListAsync()
              };
              return Ok(new Response { Code = &quot;200&quot;, Data = shipmentInitViewModel, Msg = &quot;Task Completed Succesfully&quot;, Status = &quot;1&quot; });
          }
          // GET: api/ShipmentOperations
          [SwaggerOperation(&quot;List&quot;)]
          [Route(&quot;List&quot;)]
          [HttpGet(&quot;List/{userId}&quot;)]
          public async Task&lt;ActionResult&lt;IEnumerable&lt;ShipmentOperation&gt;&gt;&gt; GetShipmentOperations()
          {
              return await _context.ShipmentOperations.ToListAsync();
          }
  
          [SwaggerOperation(&quot;Details&quot;)]
          [Route(&quot;Details&quot;)]
          [HttpGet(&quot;Details/{id}&quot;)]
          public async Task&lt;ActionResult&lt;ShipmentOperation&gt;&gt; GetShipmentOperation(string id)
          {
              var shipmentOperation = await _context.ShipmentOperations.FindAsync(id);
  
              if (shipmentOperation == null)
              {
                  return NotFound();
              }
  
              return shipmentOperation;
          }
  </code></pre>
  <p>Can anyone help me with that?</p>