Check `Response.HasStarted` in `AbpNoContentActionFilter`.

https://support.abp.io/QA/Questions/1870/Exception-in-HttpApiHost-on-non-AbpController-CSLANET

framework/src/Volo.Abp.AspNetCore.Mvc/Volo/Abp/AspNetCore/Mvc/Response/AbpNoContentActionFilter.cs

@@ -18,8 +18,9 @@ namespace Volo.Abp.AspNetCore.Mvc.Response
 
             await next();
 
-            if (context.HttpContext.Response.StatusCode == (int)HttpStatusCode.OK
+            if (!context.HttpContext.Response.HasStarted &&
-                && context.Result == null)
+                context.HttpContext.Response.StatusCode == (int)HttpStatusCode.OK &&
+                context.Result == null)
             {
                 var returnType = context.ActionDescriptor.GetReturnType();
                 if (returnType == typeof(Task) || returnType == typeof(void))
@@ -29,4 +30,4 @@ namespace Volo.Abp.AspNetCore.Mvc.Response
             }
         }
     }
-}
+}