Typically, when the SEO Analyzer scans only one page or no pages at all, it means it is getting blocked somehow from accessing your website.

Below you find our list of IP addresses for you to whitelist and avoid any issues or blockages:

94.130.93.30
168.119.99.190
168.119.99.191
168.119.99.192
168.119.99.193
168.119.99.194

It is also relevant to know the ports we connect:

For HTTP, we connect to port 80.
For HTTPS to 443 by default.

In case you already added the IPs as exceptions and are still facing issues, please check the following:

Why does the Site Audit only scan one page (or no pages) on my website?
Understanding the SEO Analyzer