Domain Problem: vercel.app with www prefix subdomain fails

I have a project called "theblueproject-landing", which is a static page. For some reason, "https://theblueproject.vercel.app" works, but "https://www.theblueproject.vercel.app" gives me a net::ERR_CERT_COMMON_NAME_INVALID error. I tried adding "www.theblueproject.vercel.app" as a domain in my Vercel project, but it didn’t work. I have already sent my CV to the admissions office of a program I’m applying to, and it contains the URL "https://www.theblueproject.vercel.app", so I need to make it work. Thank you in advance for your help.

The domain troubleshooting guide can help with most custom domain configuration issues. You might be able to use that guide to solve it before a human is available to help you. Then you can come back here and share the answer for bonus points.

https://vercel.com/docs/projects/domains/troubleshooting

You can also use v0 to narrow down the possibilities.

Vercel Staff

There is unfortunately no way to get a third-level subdomain under vercel.app. The web does not have any special treatment for www, it's just a convention to avoid putting DNS records on the root domain.

Your subdomain is already theblueproject.vercel.app and there is no way to get an SSL certificate for any further subdomains like a.b.theblueproject.vercel.app

Hi, thanks for the reply. I think I understand your explanation, but I have another Vercel project (www.sanirec.vercel.app) where www.\* works under the vercel.app subdomain without using a custom domain, redirecting to sanirec.vercel.app

Could you clarify why it’s possible for sanirec.vercel.app but not for theblueproject.vercel.app? I want to understand if there’s a configuration difference that can be fixed.

Vercel Staff

Hmm this is interesting, so it looks like we used to provide teamname.vercel.app as a convenience domain, and sanirec.vercel.app's Vercel team is named sanirec so this one works by coincidence. This is a legacy feature and generally shouldn't be relied upon, but it may work for your immediate issue

With that in mind, you may be able to fix this by changing your team slug to theblueproject

reply to #7

Hi Jacob,

Thank you so much for your reply and for clarifying the situation. I tried following your suggestion to change my team slug to “theblueproject”, but unfortunately I’m getting the message “The specified team slug is already in use.”

Is there anything that can be done on your end to free up that slug or allow me to use it? I’d really appreciate any help — I can’t change the URL at this point since it’s already been shared externally (included in my program application materials).

Thanks again for your time and support!

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