MediaWiki will not save preferences

From miscellus

MediaWiki does not save preferences

I've seen this a few times when I've been tinkering with Apache domain name settings. In my case it's been caused by the default server name being rather than or vica versa. www or non-www.

This behaviour may be modified by editing Apache settings or possibly by your server provider's admin panel.

It is also worth checking the setting of $wgServer

See also