ssl problem

SSL Problem - Insecure Connection

I am facing an issue with insecure connections on my website. I need a professional to help me fix this problem. on some devices it shows connection not secure while its working properly on other devices

Specific requirements:
- Troubleshoot and fix the insecure connection issue on my website.
- Ensure that all pages and content on my website are securely loaded.

Skills and experience required:
- Strong knowledge and experience in SSL certificates and protocols.
- Familiarity with website security best practices.
- Experience in troubleshooting and resolving SSL issues.

Hosting service:
- I use GCP (Google Cloud Platform) for hosting my website.

Please note:
- The issue only needs to be fixed on a single domain, not multiple domains.
- The SSL certificate is not expired or missing, the problem is with the insecure connection.

If you have the necessary skills and experience, and can provide a timely and effective solution to this SSL problem, please submit your proposal.