Executing endpoint '405 HTTP Method Not Supported'

I'm developing an Angular application that communicates with an ASP.NET Core backend. When attempting to call the IsRequestValid endpoint from Angular, I receive a 405 HTTP Method Not Supported error. However, invoking the same endpoint via Swagger UI works as expected.

Angular service method:

@Injectable({ providedIn: 'root' })
export class UserAppService {
private apiUrl = '/weatherforecast';

constructor(private http: HttpClient) { }

isRequestValid(input: xxxUserDto): Observable\<xxxUserDto\> {
const headers = new HttpHeaders({ 'Content-Type': 'application/json' });
return this.http.post\<xxxUserDto\>(`${this.apiUrl}/IsRequestValid`, input, { headers });
}
}


Angular component method:

this.userService.isRequestValid(this.UI_User)
.pipe(
catchError((error) =\> {
this.toaster.error('Fehler beim Validieren des Tokens.');
return throwError(() =\> error);
})
)
.subscribe((response) =\> {
this.UI_User = response;
this.setCountDown();
});


Backend controller:

\[ApiController\]
\[Route("\[controller\]")\]
public class WeatherForecastController : ControllerBase
{
// Constructor and other methods

[HttpPost("IsRequestValid")]
public async Task<ActionResult<xxxUserDto>> IsRequestValid([FromBody] xxxUserDto input)
{
// Method implementation
}

}


Serilog output:

2025-03-31 15:54:10.964 +02:00 \[INF\] Request starting HTTP/1.1 POST https://localhost:52288/weatherforecast/IsRequestValid - application/json 123
2025-03-31 15:54:11.060 +02:00 \[INF\] Executing endpoint '405 HTTP Method Not Supported'
2025-03-31 15:54:11.064 +02:00 \[INF\] Executed endpoint '405 HTTP Method Not Supported'


Vite proxy error:

15:57:02 \[vite\] http proxy error: /weatherforecast/IsRequestValid
AggregateError \[ECONNREFUSED\]:
at internalConnectMultiple (node:net:1139:18)
at afterConnectMultiple (node:net:1712:7)


What changes are necessary to successfully call the IsRequestValid endpoint from my Angular application without encountering the 405 error?

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