The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

After upgrading Magento to Magento 1.6.0.0, you may get the following message on Front-end AND Back-end:

Service Temporarily Unavailable

The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later.

In the release notes there’s a reference to this issue:

“If you see the Service Temporarily Unavailable page after refreshing the frontend, open the Magento installation directory on the server and remove the maintenance.flag file. Then go to Magento var directory and remove the cache directory”.

[email protected] [/home/xxxxxxx/public_html]# mv maintenance.flag maintenance.flag.bk

Or

[email protected] [/home/xxxxxxx/public_html]# rm -rf maintenance.flag

[email protected] [/home/xxxxxxx/public_html]# cd var/cache

[email protected] [/home/xxxxxxx/public_html/var/cache]# ll

total 72

drwxrwxrwx 12 xxxxxxx xxxxxxx 4096 Aug 7 20:55 ./

drwxr-xr-x 10 xxxxxxx xxxxxxx 4096 Aug 7 20:30 ../

drwxrwxrwx 2 xxxxxxx xxxxxxx 4096 Aug 7 20:55 mage–0/

drwxrwxrwx 2 xxxxxxx xxxxxxx 4096 Aug 7 20:55 mage–4/

drwxrwxrwx 2 xxxxxxx xxxxxxx 4096 Aug 7 20:55 mage–6/

drwxrwxrwx 2 xxxxxxx xxxxxxx 4096 Aug 7 20:55 mage–8/

drwxrwxrwx 2 xxxxxxx xxxxxxx 4096 Aug 7 20:55 mage–a/

drwxrwxrwx 2 xxxxxxx xxxxxxx 4096 Aug 7 20:55 mage–b/

drwxrwxrwx 2 xxxxxxx xxxxxxx 20480 Aug 7 20:55 mage–c/

drwxrwxrwx 2 xxxxxxx xxxxxxx 12288 Aug 7 20:55 mage–d/

drwxrwxrwx 2 xxxxxxx xxxxxxx 4096 Aug 7 20:55 mage–e/

drwxrwxrwx 2 xxxxxxx xxxxxxx 4096 Aug 7 20:55 mage–f/

[email protected] [/home/xxxxxxx/public_html/var/cache]#rm -rf mage*

Now, refresh the page and check the website. It should be working fine now.