'isAxiosError' problem with posting via this package

[jonnicholson94]

Hey

I'm sorry I don't know if this is the right place for this... I'm slightly at my wits end trying to figure out what's wrong here. It should work I think. I've tried using your package and it just won't accept my post to add a new subscriber.

I posted about this on stack overflow, here's the link: https://stackoverflow.com/questions/65355078/axios-post-in-react-front-end-leading-to-error-when-posting-to-mailerlite

Do you have any suggestions for what is going wrong here?