Make sure that all http urls are redirected to https for a more secure experience.

Here's a detailed explanation as to why you need to have this feature https://www.brafton.com/blog/distribution/how-to-convert-http-to-https-a-quick-guide/

Ask developer to ensure all of http urls are redirected to https.

There is also a plugin that can do this automatically

Blue Velvet and Really Simple SSL