[JPremium]: Could not verify a player! Error details: Connection refused

Hi, I'm using the plugin [Jpremium] so that my users can login to my server, but for days that new users can not enter for the reason "Mojang servers do not respond". I am making this report in the hope that someone can deactivate that so that new people can login to my server.

plugin: https://www.spigotmc.org/resources/%E2%96%A0-jpremium-%E2%96%A0-authorization-plugin-%E2%96%A0-automatic-login-premium-%E2%96%A0.27766/

console error: [14:05:11 WARN] [JPremium]: Could not verify a player! Error details: Connection refused

I've been in this situation for 2 days, but it still won't unlock

1- IP server: mc.zotticraft.net 
2- IP server: zotticraft.net

PS: This only happens with new accounts that have not been registered on the server before, accounts that were registered before this block can log in to the server.