Hi @adam.young
Welcome to the Prismic community.
I have found this thread that describes what seems to be the same issue.
So If the preview is working entirely on your local host, then the problem must be a configuration of the deployment service you are using.
Can you please list the npm dependencies you use in your local project to ensure that everything is up-to-date? (I personally doubt that the problem is from your code).
Also, can you add some screen recording/screenshots of the error and, if possible, the deployment platform you are using?
You can also check this thread that might help
Looking forward to your reply,
Fares