Element ref was specified as a string (inner) but no owner was set. This could happen for one of the following reasons:

[worapolburaphan]

!!! Important info
I using Next.js 6 (React SSR Library)
Node.js version 10.x.x

Do you want to request a feature or report a bug?

I'm report a bug

What's the current behavior?

When I write Calendar Component in to render method and save it, On the browser give me error below.

Invariant Violation: Element ref was specified as a string (inner) but no owner was set. This could happen for one of the following reasons:
1. You may be adding a ref to a functional component
2. You may be adding a ref to a component that was not created inside a component's render method
3. You have multiple copies of React loaded
See https://fb.me/react-refs-must-have-owner for more information.

What's the expected behavior?

I want it work on next.js

Solution that i tried already

1. npm ls react && yarn list react and it show only one react version
2. remove node_module folder and reinstall every module by npm install

[jquense]

You have multiple copies of React or react-dom. There is no other way for the library to cause this issue, and isn't anything we can do about it unfortunately. yarn and npm often don't actually report multiple copies of react, you may have to do a manual inspection.

[telnet2]

It happened to me when I used react-big-calendar with yarn link react-big-calendar. With yarn link, it automatically created node_modules/react, which doesn't exist when yarn add react-big-calendar.