When there's no ServerName directive in the global section of httpd.conf -- that's when httpd has to try to determine the servername itself. And something in the configuration of your machine, or in your name resolution, has httpd ending up with sag.visas.gov wrongly.
Add a line in the global section (you may see a commented-out example line shortly after ServerAdmin):
ServerName visas.ecvisas.com
Also change back your ServerName line in the VirtualHost section to visas.ecvisas.com.
Make sure visas.ecvisas.com is in your /etc/hosts file.
Then try restarting apache.
