what happend I lost my subdomain

Hello our best Admins It’s Pleasure to be a part of this amazing service
well I build a website here in 2016 for testing and learning I was working hard on it ,I cant upgrade right now because I am so bussy I don’t have enough time in these days, But its ok I’ll back soon , to day I got this in my free subdomain ########.fanclub.rocks which make me so sad

This domain was recently registered at Namecheap. Please check back later!

Can you Explain please thank you.

fanclub.rocks is one of the domains provided by iFastNet. I’ve messaged them to fix their DNS settings.