Firstly, thanks to SSL Labs for creating their SSL tester.
Recently I've been getting an "Assessment failed: Internal Error" whenever I try to analysis this site:
Does anyone have any idea why?
It was a bug. It's fixed now in 1.19.23, which can be found here: https://dev.ssllabs.com
Thanks for reporting the problem.
"Failed to obtain certificate and Internal Error - errors of this type will often be reported for servers that use connection rate limits or block connections in response to unusual traffic. Problems of this type are very difficult to diagnose. If you have access to the server being tested, before reporting a problem to us, please check that there is no rate limiting or IDS in place."
Maybe you have a Firewall that do some kind of DOS Protection ?If so try to whitelist SSLLabs IPsSSL Labs Known Issues
Ah, possibly they have blocked you to stop people from testing their site.
maybe this server do not block SSLLabs intentionally. I already had a similar problem causeb by DOS Protection of my FW.Cause SSLLabs scan could be misinterpreted as DOS or other threat
Your help is very much appreciated as I've now been able to run the scan.
Do you have any idea why the main scanner was able to analysis the site and then it wasn't? Does the dev version use a different IP address for scanning perhaps?
i tested already dev (as it was 1.9.19) and also failed that time. So should not source IP related.
Retrieving data ...