Errors detected in browser
In all such cases Plumbr flags the interaction containing such request as failed. In addition, the request URL along with the response code is linked with the failed request as the error due to which the interaction failed.
There are also some exceptions. First, we are not considering spans with response code 401, 409, 418 and 451 as failed because they are used a lot in REST APIs to describe behaviour of business rules and no errors or warnings are registered from such spans.
Second, pretty often response codes 400, 412 and 422 are also used to describe behaviour of business rules, but that’s not always the case – sometimes they are symptoms of genuine error. So when we first see spans with 400, 412 and 422 response codes, we do extract errors from those spans, but extracted errors are automatically demoted to warnings. Should they mean actual error for your API, you can promote them back to errors.