Uncaught Error: only one instance of babel-polyfill is allowed

This error message indicates that there is more than one instance of the babel-polyfill package being loaded in your code. This can cause conflicts and unexpected behavior.

To resolve this issue, you should ensure that you only have one instance of babel-polyfill being loaded. You can do this by checking your code for multiple import statements or script tags that reference the package.

If you are using a build tool like webpack or babel, you should also ensure that you are properly configuring your dependencies and plugins to avoid duplicate loading of packages.

Once you have identified and removed any duplicate import statements or script tags, the error should be resolved.