model-binding

I am writing a Web API with ASP.NET Web API, and make use of the following View Model. I seem to be having a problem with the data binding when there are two validation attributes on a particular property (i.e. [Required] and [StringLength(10)]). When posting a JSON value from a client to a controller action of the form: // POST api/list public void Post([FromBody] TaskViewModel taskVM) I observe the following: If I remove one of the multiple attributes everything is bound OK; If I leave in the multiple attributes, the client recieves a 500 internal server error and the body of the Post method

I am writing ASP.NET Core 2.2.0 application hosted on Service Fabric. I have a class which represents a request and I have declared two constructors: public for my own usage and private for serializers: public class MyClass { private MyClass() // for serializer { } public MyClass(string myProperty) // for myself { MyProperty = myProperty ?? throw new ArgumentNullException(nameof(myProperty)); } [Required] public string MyProperty { get; private set; } } Then, I created an API controller: [ApiController] public class MyController { [HttpPut] public async Task<IActionResult> Save([FromBody]