Hello,
One of our customer was facing issue with his Magento website. He was suddenly receiving following error:
QuoteThe server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.
Solution :: You see this page because of site is in maintenance mode now. Login to your server via ssh over the root user and remove the file
maintenance.flag from document root of domain.
Quote#rm-f /home/usernmae/public_html/maintenance.flag
Now refresh the page. You should see your website is working fine now.
Enjoy !!