It seems like you are currently using a Self Signed certificate (Not trusted) with your site, try using an SSL/TLS by using Cloudflare to enable secure connection. You can either enable Cloudflare via vPanel or at the Cloudflare site directly.
You could also add a certificate via the certificate creator in the client area, adjust wp-settings and then upload the certificate the the c/vPanel. This may be better, since if you don’t configure Cloudflare correctly your WordPress site could break.
sir, I have uploaded certificate successfully in Cpanel. But still facing this error. you can see the attached image as there is lock symbol. But still this error. Sir should I go for Cloudflare