Codex Fails to Launch: "The 'gpt-5.2' model is not supported when using a ChatGPT account"

What version of the Codex App are you using (From “About Codex” dialog)?

ChatGPT 26.707.72221

What subscription do you have?

no

What platform is your computer?

CODEX

What issue are you seeing?

When I open Codex in the ChatGPT macOS application, I immediately receive the following error message:

"The 'gpt-5.2' model is not supported when using Codex with a ChatGPT account."

The error appears instantly and prevents me from using Codex at all. I do not have any option to change the model from the interface.

What steps can reproduce the bug?

Open the ChatGPT desktop application on macOS.
Sign in with a ChatGPT Free account.
Navigate to Codex.
The error appears immediately before any interaction can be performed.

The issue occurs every time and is fully reproducible.

What is the expected behavior?

Codex should open normally and use a supported model for my account, or provide a model selector if the currently assigned model is unavailable.

The application should not attempt to use an unsupported model and block access to Codex.

Additional information

Incident ID: no-active-thread-019f63a5-0dd5-7333-af2d-64e1bc3b41d2
Device: MacBook with Apple Silicon M3
App Version: ChatGPT 26.707.72221
Account Type: ChatGPT Free
Downloaded from the official OpenAI website
Already tried:
Signing out and signing back in
Restarting the application
Verifying the application is up to date
No model selection option is available in the UI
The error occurs immediately after opening Codex