Check robots.txt
ArvaSEO-Bot follows your robots.txt. If it says Disallow: / for all crawlers or for ArvaSEO-Bot, the audit stops. Allow it, or remove the rule.
Check your firewall or CDN
Security services can block or challenge crawlers. Allow the user agent ArvaSEO-Bot (it identifies itself as Mozilla/5.0 (compatible; ArvaSEO-Bot/1.0; +https://arvaseo.com/bot)).
Check how pages are linked
The crawler follows links from the homepage. Pages that nothing links to, or that only appear after a login or a search form, can't be found. A sitemap linked from robots.txt helps.
Check your allowance
Each page uses one crawl credit. If the month's credits run out, the audit stops early; the audit page says so.