I am using namecheap as hosting my website was using namecheap SSL certificate but i decided to change to Cloudflare, when i change the nameservers to Cloudflare my website is not loading properly and i get this page
Looks familiar to me.
I also have domains at NameCheap too.
Under your NameCheap account to to Domains, find your desired one and deactivate the Parking Page following below article - just make sure you click on “Turn Off” button (instead of Turn on):
More information about parking page here:
Thank you for feedback information.
Seems that’s disabled and off as it should be.
May I ask you to post and share your domain name in bracketed dot [.] notation here with us so we could double-check, troubleshoot and provide some feedback information? 
I wonder if the Cloudflare nameservers are copy-pasted correctly into the custom nameservers field, therefore clicked on the green checkmark icon 
to apply the changes in the Namecheap interface.
Or maybe you’ve entered the given Cloudflare nameservers under the Advanced DNS tab → Private NS?
