Transmission error

So, my WordPress site domain comes from Godaddy and is hosted on a Hong Kong server because our target users are mostly from Hong Kong. If I want to improve SEO and start sending backlinks to directory sites, I always get the error message "The URL could not be verified, either the page does not exist or the server is unreachable."
SEMrush

I've read from another platform that someone commented: You get the error because you're using SSL that belongs to someone else. If these directories try to validate your site using https, a warning message will appear warning you that your site may be harmful and that third-party SSL is the reason. My suggestion would be to buy SSL directly from your web host or from a legitimate SSL company. "

But unfortunately I can not guarantee if this is the right way and how I can do that.
Could someone please teach me? Incidentally, my website is a link, hopefully you'll find some pointers with the link. Thank you in advance.
https://www.bananaportal.com/