FTP Server tests, configured with a Request Type of "Download" and with "Limit Download Size" not enabled, were reporting failures.  As a temporary measure,  Errors and Alerts could be cleared by enabling "Limit Download Size" and specifying any value (in kB). 

Affected scope

FTP Server tests with the following settings were affected: 

• Request Type: Download
• "Limit Download Size" not enabled

Errors and Alerts could be temporarily resolved by enabling "Limit Download Size" within the test settings and specifying any value (in kB). 

Status

The issue is resolved. If you're still seeing this error with your Enterprise Agents please ensure they are able to successfully update to te-agent version 1.53.1
 

Event timeline

2019-01-08 02:45 UTC: Fix has been deployed, Agents running the latest te-agent version 1.53.1 no longer exhibit this behavior. 
2019-01-07 15:00 UTC: Issue resolution process ongoing - the proposed fix is being tested internally.
2019-01-07 07:00 UTC: Issue identified. Engineering team is working on a resolution.
2019-01-07 05:30 UTC: Event detected by ThousandEyes service reliability team, investigation started.
2019-01-07 04:30 UTC: Some FTP tests begin to show failures