Hi,
I´ve got JMS Version 1.2.19 on Centos Server with plesk.

To create a slave site in sub-directory with Symbolic Link allowed in the back-end y must to modify multisites.cfg.php to chmod 777 and it work fine but when I try to create a new slave site in Front-End appear the message:
"

* Unable to create the symbolic link [administrator] -> [/var/www/vhosts/domain.com/httpdocs/administrator]...

Can you help me please?

The keyword in your question is PLESK.

On plesk system, if you try to deploy a slave site into another directory than the master website, you need to change the plesk permission.
By default Plesk protect all the directories with owner, permission and "open_basedir".
In your case, I suspect that you try to deploy the slave site for a subdomain or another domain that plesk declare iin a directory beside the master.

That mean that you have to contact you Plesk administrator to ask him change the Plesk permission.
He will have to change the "open_basedir" of your website to give permission to the directory.

If you need that we assist you in such configuration, this is possible with billable support.
This may take several hours to setup plesk.

You can know the value of the "open_basedir" when you go in the Joomla / Help / System info / PHP Info

Thanks,

I change the open_basedir to give permission to directory var/www/vhosts/domain.com/httpdocs/multisites but it appear te same error.

Any Idea please?

Thanks

Celso

It is not good.
You have to provide the open_basedir with both the master AND slave directory.
All the access or event put it with "no value" to give permission to all the directories.

Ok I made this change and now appear this message
"open_basedir no value no value"
in Joomla / Help / System info / PHP Info but I´ve got te same problem.

Thanks

Check that you have the option follow symbolic link allowed in the plesk configuration

recheck the file permission and folder
Mainly if this is different owner/groups