Connecting Angular Front to Spring Boot Back

So I have an Angular front end hosted on firebase. I have a Spring Boot backend hosted on digital ocean. I want to enable full encryption between my front and my back. I installed the key and certificate into a .p12 and my Spring Boot application seems to connect with it and access it correctly. I haven’t done anything on Digital Ocean besides that.

I have a test endpoint that I am trying to hit from my front end. I can use postman to hit the endpoint, however, when I try to hit the endpoint through my hosted Angular app I get “net::ERR_CERT_AUTHORITY_INVALID” in Firefox, Chrome, and Edge. Nothing goes through to my backend.

If I go to the endpoint in my browser and select that I trust, it works, but I get this message:

"This site has a valid certificate, issued by a trusted authority.

However, some parts of the site are not secure. This means information (such as passwords or credit cards) might not be securely sent to this site and may be intercepted or seen by others."

Does anyone have any ideas on what I could be going wrong?

Okay, so I have been thinking about this and I figured out what the problem was.

So I had a domain name for my front end on firebase. However, I didn’t have a domain name for my backend API on digital ocean. So I had to purchase a domain name for my backend and configure it to point to my digital ocean server through cloud fare.