Add info for missing error message and stack trace (#24297)

* Add info for missing error message and stack trace

* Update content/en/tracing/troubleshooting/_index.md

Co-authored-by: Ursula Chen <[email protected]>

* Add link target

---------

Co-authored-by: Ursula Chen <[email protected]>

content/en/tracing/troubleshooting/_index.md

@@ -108,6 +108,16 @@ Including metric partitions or grouping variables in service names instead of ap
 
  For example, instead of the service `web-store`, you might decide to name different instances of a service `web-store-us-1`, `web-store-eu-1`, and `web-store-eu-2` to see performance metrics for these partitions side-by-side. Datadog recommends implementing the **region value** (`us-1`, `eu-1`, `eu-2`) as a second primary tag.
 
+### Missing error message and stack trace
+
+In some traces with an error status, the **Errors** tab shows `Missing error message and stack trace` rather than exception details. 
+
+A span can show this message for two possible reasons:
+- The span contains an unhandled exception.
+- An HTTP response within the span returned an HTTP status code between 400 and 599.
+
+When an exception is handled in a try/catch block, `error.msg`, `error.type`, and `error.stack` span tags are not populated. To populate the detailed error span tags, use [Custom Instrumentation][18] code.
+
 ## Troubleshooting data requested by Datadog Support
 
 When you open a [support ticket][1], our support team may ask for some combination of the following types of information:
@@ -174,3 +184,4 @@ kubectl exec -it <agent-pod-name> -c trace-agent -- agent flare <case-id> --loca
 [15]: /tracing/compatibility_requirements/
 [16]: /tracing/guide/setting_primary_tags_to_scope/?tab=helm#add-a-second-primary-tag-in-datadog
 [17]: /tracing/guide/setting_primary_tags_to_scope/
+[18]: /tracing/trace_collection/custom_instrumentation/?tab=datadogapi