how to disable nickname in muc??

Join a new room, configure it using your Jabber client, and among other options you will see one to Allow visitors to change their nickname. Disable it.

If you want all the rooms to have that option disabled by default, then edit the ejabberd configuration file, and use the mod_muc option default_room_options to set allow_visitor_nickchange: false

tnx for your replay
i use the your trick but also users can change their nickname in room!!! this option not work for me. there is no way to resolve the problem?
users can register nickname in Service Discovery and set nickname another users for their !! and another users can not join to any rooms!

please help

Does this option appear as false when you load configuration for that room ?
It may be a syntax problem in your config file.

yes i set this option to false in muc module defaults.
why this option not work for me? this is worked for you?
aftar me start the ejabberd, no problem and errors showed

please help

My previous question was not about your config file but about checking what the config form of a default MUC show when you load it in an XMPP client.
Does it show the correct option under that condition ?

I am trying to determine if the option is not properly set or if it is not correctly applied in code.

Thanks !

oh sorry
yes this option correctly showed in client and room configure for this option is no mark .
now me ejabberd redirected to version 2.1.10
i sea many server in around in my country, server admins try to disable it but just nickname change disable not work for their.

what is your config for your server for this option?
i confiused why it not work

my room configure screen shoot:
http://qfs.mobi/f2259840

Firstly, you should use ejabberd 15.04. ejabberd 2.1.10 is very old.
Secondly, other people are having success with this option so I suspect you syntax configuration is incorrect.

me now installed new version but it now not work
if my config file have syntax, why my ejabberd started correctly?
can you terminate this for me? i want send access for you to check it.

mremond help plz
my problem not solved