I just was trying to change Squirrel mail lenguage i did:
sudo locale-gen es_ES
and then
service apache2 restart
the result:
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root@server3:/home/srv3# /etc/init.d/apache2 restart
* Restarting web server apache2 Action 'start' failed.
The Apache error log may have more information.
[fail]
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i dont know if it was problem of the lenguage change or what