Step-by Step fixed for Error 521 Web Server Down.
GOOGLE SEARCH ENGINES URLs
Keyword(s) URL with %s in place of query
google
g ; Search with Google Search Engine (if it is not your default)
www.google.com...%s
gdrive
gd ; Search Google Drive
drive.google.c...%s
gimages
img ; Search Google Images
www.google.com...%s
gmail
gm ; Search Google Mail
mail.google.co...%s
gcontacts
gmc ; Search Google Mail Contacts
mail.google.co...%s
gmaps
maps ; Search Google Maps
maps.google.com...%s&ie=UTF8&z=12&iwloc=addr&om=1
ggroups
gg ; Search Google Groups
groups.google....%s
ghistory
gh ; Search Google History
chrome://history/#q=%s&p=0
gplus
g+ ; Search Google Plus
plus.google.co...%s
gtranslate
gt ; Search Google Translate
translate.googl...|auto|%s
youtube
yt ; Search Google's KZfaq
www.youtube.com...%s