Hi @Katkat ,
In which region your Open AI resource is? As mentioned in the documentation, there are limited availability of GPT-4 models in East US/East US 2 and France Central region, and this could be preventing you from deploy a new GPT-4 model in East US.
I suggest you to please use your other GPT-4 model versions and a different region like Canada East, Sweden Central and Switzerland North which is available for GPT-4 model creation.
Sorry for the inconvenience this has caused you.
Please let me know if you have any other questions.
Thanks
Saurabh