I'm just learning but I experienced the same error try to purchase a Paid plan and trying to submit a request to openAI the other day.  I was getting these errors for most of the day as I tried repeatedly, with plenty of pauses in between.  Then finally late at night everything started working.  I just took it as the openAI server were overloaded with "too many request."  Might not be your problem though.

All sorted, it was a billing issue after all.
Any chance of showing the usage amount left in the account on the form?

Have you looked at the OpenAI API to see if there is an endpoint to get that info?

Not sure myself how the billing works.  I have a subscription for GPT4 through Apple, put funds into the account via my online login, thought all was good but was apparently just running off the free trial.  Added funds via the screenshot method, seems to be working for now and can see the credit.  Don't know where the previous money was allocated to in the account?

Alex, had a go asking GPT to do this, its requiring JSON, I know nothing about it.

Another member asked about JSON parsing in this thread: Parse JSON function

Thank you, looks like he takes the time to explain, I will give it a go, good to learn something new.