My memcache is timing out. Does anyone know why?

Question

I am using memcached and python-memcache. On my cache server, iptables is set perfectly, and it's allowed:

ACCEPT     all  --  dev                  anywhere

The process is this:

/usr/local/bin/memcached -d -u root -m 3900 -p 11211

I do this in Django but it's not working. It times out at cache.set.

cache.set("test","laa",333)
print cache.get("test")

Awkwardly, it works on my other web2 server, just not this one:

tcp        0      0 cache1:11211            web2:57019              ESTABLISHED