Hi Martin BEDNAR,
Welcome to the Microsoft Q&A Platform! Thank you for asking your question here.
It is a known issue, and Product Team is working on rolling out a fix across all the regions. As a work around you can use this private link for resource creation via portal.
https://ms.portal.azure.com/?feature.canmodifystamps=true&Microsoft_Azure_ContainerService=flight40#home
or you can use the following link [0] to use the Azure CLI. Please chose to use the Azure Cloud Shell within the Azure Portal to run the commands.
Azure CLICopy
# already created a Resource Group via webui and had uploaded a Container Image
az container create --resource-group RESOURCE_GROUP --name CONTAINER_NAME --image IMAGE --registry-login-server SERVER --registry-username REGISTRY --registry-password PASS --ip-address Public --dns-name-label SOMENAME --ports 80
az container list --resource-group RESOURCE_GROUP
az container delete --name CONTAINER_NAME --resource-group RESOURCE_GROUP
az group list
az group delete --name RESOURCE_GROUP
[0] https://zcusa.951200.xyz/en-us/answers/questions/2078125/issue-with-missing-ip-address-fqdn-when-provisioni
https://zcusa.951200.xyz/en-us/answers/questions/2083328/fqdn-not-shown-for-azure-container-instance