Troubleshooting HTTP Monitor Error/ Health Status Codes

[HannahM]

• Summary
• Where to find HTTP Monitor Error/ Health Status Codes
• Error/Health Status Codes and Suggested Actions
• Where to find HTTP Monitor Logs
• What's next

Summary

This article provides the most common error codes seen in Dynatrace Synthetic HTTP monitors, notes on the behavior, and some troubleshooting suggestions. 

Where to find HTTP Monitor Error/ Health Status Codes 

HTTP Monitor executions don't always succeed. In addition to the HTTP response codes that a request can return, there are several Dynatrace error codes. 

A summary of the HTTP Monitor error codes for a period can be seen in the HTTP Monitor details> Failed Requests card. 

You can also, find the error code for the most recent failed, successful and on-demand executions in Analyze last failed execution. You can filter the JSON to just show the error. In the JSON the error code is called HealthStatusCode and the error description is HealthStatus. 

Error/Health Status Codes and Suggested Actions

Error/ Health Status Code	Error Description/ Health Status	Suggested Actions
0	Healthy
1	SSL Communication error	Check vuc-http-execution.log for more details.
2	DNS query timeout	Check vuc-http-execution.log for more details.
3	Unknown Host	Check nslookup from the ActiveGate.
4	Unexpected Error	Check vuc-http-execution.log and vuc-http.log for more info
5	Redirects not allowed
6	Invalid Code	Status Code validation failed Check Monitor> Settings>HTTP Requests> Request> Response Status Code Verification setting
7	Script execution failed	Check vuc-http-execution.log for more details.
8	Script Fail	Check vuc-http-execution.log for more details.
12	Http Monitor Execution Timeout	Use Adapt Request Timeout to increase up to 60s. The HTTP Monitor Advanced settings preview can be used to increase the monitor timeout. Ask your CSM or Support for more details.
13	Too many redirects	The maximum number of redirects for synthetic monitors is 10. When a monitor reaches 11 redirects, it fails with this error.  Reach out to your application team to find out why there are so many redirects and reduce them.
15	Connection timeout	Test connection using curl from the ActiveGate Is a proxy needed? If a public location, is this endpoint available? Do the public location IP addresses need to be allowlisted by the application?
16	Connection Refused	Does this endpoint require specific headers to be added? Private location: Test connection using curl from the ActiveGate. Is a proxy needed?  Public location: Is this endpoint available? Do the public location IP addresses need to be allowlisted by the application?
17	Constraint Violated value	Response validation failed. Check Monitor> Settings>HTTP Requests> Request> Set rule for response validation setting
18	Unknown Method Error	Check vuc-http-execution.log and vuc-http.log for more info. This occurs when a method is called in the pre-/ post- execution script that the monitor is unaware of. These are usually from third party libraries. For these situations, you must add the code for the function into the script. Like these examples here and here
20	SSL Expiry warning
24	Request Timeout	Test connection using curl from AG Is a proxy needed? If a public location, is this endpoint available? Do the public location IP addresses need to be allowlisted by the application?
30	Forbidden URL Error	IP resolves to localhost, which, due to security reasons, is not allowed

Where to find HTTP Monitor Logs

You can either download the support archive or check directly on for HTTP Monitor logs on a Private location. You can find where to check here.

What's next

Open a chat or contact support if 

• you need to check the logs for an HTTP Monitor running on a public location, or
• the issue is still not resolved after taking the above actions

[ChadTurner]

Thanks for sharing this out @HannahM 

[ct_27]

@HannahM  This is awesome, can this information be posted on the public documentation site? The table you created is so informative. We were just having problem #7 and we found this post while troubleshooting.  So valuable.

[nadeem_m]

@HannahM Very Informative!