Why did I receive this error message "Please insert reference outside of content control?"
This is because you likely have included unrecognized text where a CiteRight field should be. Here's how that works. CiteRight wraps a reference in something called a content control. This is loosely defined as a container for any kind of field in Word. Further more, CiteRight only allows for one field per content control.
That said, when you insert text outside a CiteRight field but still within the content control, CiteRight thinks that you are trying to add another field within one content control.
You'll get the error if your cursor is outside the field highlighted in gray but still within the box surrounding the field.
You'll also get the error if you've typed other text then try to cite the reference in the same content control, like this:
In both of the above cases you'll receive the content control error message.
How to resolve it
Simply move your arrow keys on your keyboard outside the content control or click on another area of your document to move outside the content control.