If it isn't you shouldn't and can't connect your main/root domain (i.e. www.companyA.com) but rather create and connect a subdomain, i.e. blog.companyA.com or content.companyA.com.
Can you share a screenshot of your HubSpot domain settings?
Frank
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My website says error 404 after connecting with HubSpot
Hi @MTGD-Media , the first place I'd check is the language settings, the default has language URL redirects enabled which can cause your URL to not match what you're expecting it to be.
Assuming of course you've verifed the DNS settings and have no errors.
Let me know if you're still getting the 404 and we can look at a few other settings.
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