I read the message in the plugin page and i want to know if i can use that plugin in my server with the author permission. Thanks.

This plugin is unlicensed and the original author reserves all rights to it.
The original author may request that this plugin be removed and there is a risk that the plugin may be unavailable in the future.
Note that the current maintainer may not have permission to assign a license to the plugin if they are not the original author, so explicit permission would need to be obtained from the original author in order for the plugin to remain openly available and guarantee that it will be around for all to enjoy going forward.

The main reason that text is there is that it could be pulled and be unavailable should the author choose to, being as it isn't licensed. You can use it, but the warning is there to let you know this.

Then I can use but if the author tells me to remove it from my server I have to.

There is another similar plugin just in case the author tells you to remove it??

No, you'd be fine. It is about it being in our site, that's it.

Ah okey. Thanks Wulf.  "Wooof" XD

Message for Author: Please mate don't delete it. We l♥ve you xd