This template is ONLY for reporting security bugs. If you are reporting a
Download Protection Bypass bug, please use the "Security - Download
Protection" template. For all other reports, please use a different
template.

Please READ THIS FAQ before filing a bug: https://www.chromium.org/Home
/chromium-security/security-faq

Please see the following link for instructions on filing security bugs:
http://www.chromium.org/Home/chromium-security/reporting-security-bugs

NOTE: Security bugs are normally made public once a fix has been widely
deployed.

VULNERABILITY DETAILS
My site was returning error 503, & PageSpeed Insights gave me highest rating I could ever get. 
Please refer this screenshot
https://www.diigo.com/item/image/5tasn/7moh

VERSION
Chrome Version: [x.x.x.x] + [stable, beta, or dev]
Operating System: [Please indicate OS, version, and service pack level]

REPRODUCTION CASE
Please include a demonstration of the security bug, such as an attached
HTML or binary file that reproduces the bug when loaded in Chrome. PLEASE
make the file as small as possible and remove any content not required to
demonstrate the bug.

FOR CRASHES, PLEASE INCLUDE THE FOLLOWING ADDITIONAL INFORMATION
Type of crash: [tab, browser, etc.]
Crash State: [see link above: stack trace, registers, exception record]
Client ID (if relevant): [see link above]