Why async method in ASP.NET 5(Core) is not responding?

Question

ASP.NET

Hello, I ran into the following problem: there is an async method, when I send a request to it from the browser, the method is completely executed (which is written in the console) and returns a response, but the browser continues to wait for a response. If the server is stopped at this time, the browser will show the answer, if not stopped, then after a while a white screen will simply remain. How to fix it? Thank you.
(HttpGet for simplicity, then I'll change it into a post)

[HttpGet("{userName}/{password}")]
        public async Task<string> Get(string userName, string password)
        {
            if (ModelState.IsValid)
            {
                var user =new ApplicationUser()
                {
                    UserName = userName
                };
                var result = await usrManager.CreateAsync(user, password);
                _logger.LogInformation(result.ToString());
                if (result.Succeeded)
                {
                    _logger.LogInformation(result.Succeeded.ToString());
                    return "{'errorCode': '0'}";
                }
                else
                {
                    _logger.LogInformation(result.Errors.First().Description);
                    return "{'errorCode': '1','description':'"+result.Errors.First().Description+"'}";
                }
            }
            return "Internal error.";
        }

Answer 1

Most likely deadlock somewhere