Using OpenAI-ChatGPT with Drafts

I installed this gpt-4 action item but it did not work. However, the gpt-3 version works.
I deleted (forget) the gpt-3 entry in the Drafts Credential setting and used a new gpt-4 API code, as I have access to the paid gpt-4 version. It’s still not working. What am I not doing right?