Well, if you produced the website, you should hopefully be in a position to investigate why it is getting flagged. I would suggest:
Put the site name into
https://www.ssltrust.co.uk/ssl-tools/website-security-check
and review the errors that come up. When I did it, it returned a warning from GDATA about malware but that was the only one and may be historical. You can request GDATA to remove a false-positive via a URL submission here
https://www.gdatasoftware.com/faq/consumer/submit-a-suspicious-file-app-or-url
You can also make removal submissions via the blocked.org.uk website by putting your URL in there and requesting unblocking
The other issues reported were due to SSL certificate problems. If you do not deal with those for the site (e.g. you are just using a hosting company and CMS), then you should refer the issue to the hosting company for the website/domain name.
Hope that helps.