HELP!! 45% of people not able to access my our ecommerce site via their wifi internet

Site URL: https://gohsh.com

Hi! Can someone help? We're getting ready for our launch and feedback has been that people are unable to access our site. They're getting malware or cautioned about security. Squarespace told me it could be an SSL certificate issue. People are able to open our site via gohsh.squarespace.com but if it's through our direct domain, they're warned or blocked. It's happening mostly happening on optimum online customers, people using their work computers and also overseas globally. Does this mean I have to just move over to Shopify?? 😞