I can not add my website to the directory submission sites …

I did not find the explanation of the problem here. My website is Smart Line (https://www.ismartline.com/en/). When I submit my link to web directory submission sites, I used to get the message This error message.

"The URL could not be validated. The page does not exist or the server could not be contacted."

I've always tried to submit the site with http, www, without www. but the problem persists. How can I solve this problem? Are there any other ways to submit websites to sites directories enabled for https?

Please help me?