This browser is no longer supported.
Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support.
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(188.79999999999998, 42%, 28%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EHV%3C/text%3E%3C/svg%3E)
The deployment of the public IPv6 address in the Microsoft tenant failed with the following error:
DNS record mydns.cloudapp.azure.com is already reserved by another resource. (Code: DnsRecordIsReserved)
To investigate, I searched across all subscriptions using the command below to identify the resource currently holding this DNS label so that it could be released. Unfortunately, I was unable to find any resource associated with this domain.
''' for sub in $(az account list --query "[].id" -o tsv); do
echo "Checking subscription: $sub"
az account set --subscription $sub
az resource list \
--query "[?tags && contains(to_string(tags), 'edu-lcereading-int')].[name, type, resourceGroup]" \
-o table
done '''
I also attempted to create a new public IP manually using the same DNS label but received the same error again.
Could the support team please help verify whether this DNS label is still reserved by an existing or orphaned resource, and if so, assist with releasing it? Please note that the DNS record was registered by our team in OneCert on April 21, 2026
An Azure service that enables hosting Domain Name System (DNS) domains in Azure.
Answer accepted by question author
![](data:image/svg+xml, %3Csvg xmlns='http://www.w3.org/2000/svg' height='64' class='font-weight-bold' style='font: 600 30.11764705882353px "SegoeUI", Arial' width='64'%3E%3Ccircle fill='hsl(192, 23%, 28%)' cx='32' cy='32' r='32' /%3E%3Ctext x='50%25' y='55%25' dominant-baseline='middle' text-anchor='middle' fill='%23FFF' %3EVV%3C/text%3E%3C/svg%3E)
Hi @ Hoa Vo (Centific Technologies Inc),
Welcome to Microsoft Q&A Platform.
As discussed, the endpoint is reserved in the another tenant and cannot be used in the test tenant. Alternatively, please use a different name or create a new one for the Azure Public IP.
Please
and “up-vote” wherever the information provided helps you, this can be beneficial to other community members.
Hi,
DNS names in this case need to be unique by all azure tenants and are not scoped only to your tenant. The domain .cloudapp.azure.com is used by all other tenants in Azure so someone other customer registered mydns. If you want your own friendly dns name you need to use custom domain. For this you will need your own DNS provider or use Azure DNS.
Note that once you have released a dns name for those domains owned by Azure you cannot retain it. It is free for some other tenant to take it. If you want to be able to retain the DNS name you will need to use Domain Name Label Scope in case you delete the public IP and you want to create it with the same name so you can receive the same domain name.
A list of Azure owned domains (not customer owned).
Please "Accept the answer" if the information helped you. This will help us and others in the community as well.