Hey there, So the details of the errors you're looking at are usually errors/responses returned by the server or requests attempting to leave the browser. An XHR that is canceled isn't really an error but usually is something on the browser level that gives up to make that request.
that being said you won't be able to monitor a request like that. It produces no error message, no response code, and sometimes canceled xhrs can occur frequently for users depending on how the web application is set up. (loading a new page in a middle of an xhr for example) so Dynatrace not capturing it makes sense.