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/domains/troubleshooting

vercel.com

Troubleshooting domains

Learn about common reasons for domain misconfigurations and how to troubleshoot your domain on Vercel.

Hi William,

For separate Vercel accounts/projects, the key issue is domain ownership verification.

If Vercel does not treat is-app.top or til.my.id as a public/shared suffix, then a user adding something like:

1
my-site.is-app.top
2

may still be asked to verify ownership at the parent level, for example:

1
_vercel.is-app.top
2

That would not work for individual users, because they only control their assigned subdomain, not the whole parent domain. That restriction is intentional, otherwise anyone could try to claim subdomains under someone else’s registered domain.

Without PSL/shared-suffix handling, I think the practical options are:

1. Keep the wildcard domain in your own Vercel account/project, for example *.is-app.top, and route users by hostname inside one multi-tenant app.

2. Have users use their own custom domains instead of your shared suffix.

3. Pursue PSL / Vercel-side shared-suffix recognition later, so Vercel asks users to verify at the subdomain level instead of the parent level.

A useful test would be to have one user try adding a sample subdomain to their Vercel project and note the exact TXT record Vercel asks for. If it asks for _vercel.<user>.is-app.top, you can probably automate that in your DNS. If it asks for _vercel.is-app.top, then the multi-account model will not scale without PSL/shared-suffix support.

Hello, Ryu

Thank you for your answer.

So, can I ask Vercel to add these two domain names to its suffix list?

I just want everyone to be able to use it on Vercel.

Hi William,

You can ask, but I would not assume Vercel can or will manually add private suffixes just from a Community post.

For Vercel to safely let unrelated accounts add domains like:

1
user.is-app.top
2
user.til.my.id
3

without requiring verification of the parent domain, Vercel needs to know that is-app.top and til.my.id are shared/public suffix boundaries. The standard way to express that across platforms is the Public Suffix List.

So I’d think of it like this:

1
Best long-term path:
2
Add is-app.top and til.my.id to the Public Suffix List.
3

4
Then:
5
Ask Vercel to make sure their internal suffix data recognizes the updated PSL entry.
6

If the domains are not in PSL, Vercel may continue treating is-app.top as one privately owned domain. In that case, asking each user to verify only their own subdomain would be a security risk, because Vercel has no general way to know which subdomains you assigned to which user.

For now, the practical workaround is still to keep the wildcard domain in your own Vercel project/account:

1
*.is-app.top
2
*.til.my.id
3

and route by hostname inside your own multi-tenant app, instead of having each user attach the subdomain to a separate Vercel account.

If you open a request, I’d include:

1
Domains: is-app.top and til.my.id
2
Use case: free community subdomains
3
Need: allow different Vercel accounts to verify only their assigned subdomain
4
Current blocker: Vercel asks for parent-domain verification
5
Long-term plan: PSL/shared-suffix recognition
6

Hi, Ryu

Thank you again.

How can I contact Vercel support to open a request?

Update: Subdomains can be used across accounts with a simple access verification step. Vercel respects the Public Suffix List when treating a domain as an eTLD. You should NOT submit a request to add your domain to the PSL unless it is actually appropriate for inclusion in that list (see guidelines)

@willi-felix You need to get the domain added to the Public Suffix List and then let me know here after it's added so I can make sure Vercel's internal list is synced

Related topic for more info: https://community.vercel.com/t/is-a-dev-domain-issue/923

Vercel Community

Is-a-dev domain issue

Hello! I am a maintainer of is-a-dev, a free subdomain service. We are registered with the PSL and our users want to connect their is-a-dev domains with...

Hello Amy,

I also tried adding the domain name to the Public Suffix List (PSL), but due to the low number of people who know about and use it, our domain name has not yet been recognized by the PSL maintenance team.

I want to try contacting Vercel to I'd like to try contacting Vercel to get support from the platform, allowing me to use these two domains without adding them to PSL, with the goal of attracting more users.

Once the domain has a user base, adding these two domains to PSL will be the first thing I do.

Vercel will not add it as a public suffix unless it is already on the Public Suffix List