SEO/ahrefs problem

I have the following topic, please help: I cannot scrawl on page tippinsider.com for outgoing links. It says: 503 server not available. But I can open the site easily in Chrome. What's the issue? Any blocking code from their SEO?

Sites can block incoming requests quite easily, in Cloudflare for instance you can block whole servers by ASN including the servers Ahrefs uses.

However, 503 code seems strange, as this one should mean the server doesn't respond. Maybe some mixup.

what's the problem you facing?