I can access your site from both the domain and the IP.
I can see your certificate is valid and it expires on 21 September 2020, so I guess you managed it to work.
However, you have mixed content. You could check it by accessing your browser developer console.
Mixed Content: The page at 'https://www.XXXXXXX.XX.XX/' was loaded over HTTPS, but requested an insecure image 'http://XXX.XXX.XXX.XX/...'. This content should also be served over HTTPS.
In order to fix it, you need to replace those links with HTTPS to get rid of the warning. This previous answer may help: