Browsers on my mac are viewing old SSL certificates and won't open new site
My website bucksccc.org.uk, was recently moved to a new host, DNS changed and SSL certificates renewed. The new site works wonderfully on everyones Macs, PCs, Tablets, phones etc all over the globe. But not my Mac. When I type in the URL ALL browsers say the site is insecure and they will not open it. When I look at the SSL certificate that is being rejected, it is the old one from the old host. On my mac I also have Windows 10. The site opens fine on there and the certificate is correct. It is something on my Mac that is obviously causing this. I have refreshed Firefox, rebooted, cleaned cache, flushed DNS cache, etc, etc, but still have not found a fix.