Custom domain help

I recently joined cloud fare so I could have a custom domain On my website! I use a property management software through Hostfully. The portion of their site that controls bookings has a really long non custom domain. After following all of the instructions my domains are all messed up. My domain is through squarespace. Not sure where I went wrong setting this up. Now my custom domain through squarespace is wrong and messed up. Any help is appreciated!