Hi! Welcome to the forum! Take note that the issue in the DNS propagation has no correlation to the SSL certificate issue. Please do not merge two different topics next time.
The https version of the website may not work because your website does not have any SSL certificate installed. If you want it, then consider installing any SSL certificate from any SSL provider to the website. Infinityfree offers free SSL installation tool in the client area. For more information, kindly refer to: