We're sorry to hear about the issue you're having when you try to create a new book or course. Also, our apologies for the unhelpful error message.
The best thing to do in this case is to create an account first:
After you do that, you should be able to create a new book or course, without getting the error message.
If that does not resolve the issue, if you could let us see a screenshot of the form before you click the submit button, that might help us see what's causing the issue.
Sorry about this, normally it just works!
UPDATE: Please note that a customer has reported to us that this may happen if you are getting blocked by the reCAPTCHA service (and you may also get the unhelpful error message "Please review the problems below:", but not see any errors to review).
If you are using an ad blocker or a VPN or something like that, that might explain the issue.
Also, you might want to try creating an account on another device.
If you still have trouble signing in on your main device, after you have created an account, you may still be able to sign in on your main device, by using the password reset process:
We hope this information helps, and you find a way to create an account and get signed in.