Only plain objects can be passed to Client Components from Server Components
Only plain objects, and a few built-ins, can be passed to Client Components from Server Components. Classes or null prototypes are not supported.
React threw this error because a Server Component attempted to pass a non-serializable value into a Client Component. This often happens with class instances, custom prototypes, or complex objects that cannot cross the server/client boundary safely.
Only plain objects, and a few built-ins, can be passed to Client Components from Server Components. Classes or null prototypes are not supported.
Why it happens
A Server Component passed a class instance into a Client Component.
A custom object with a null prototype or non-plain prototype crossed the server/client boundary.
A complex non-serializable value was returned from server-side data logic and fed directly into a Client Component prop.
How to fix it
Convert the value to a plain serializable object before passing it to the Client Component.
Pass only the specific primitive fields the client actually needs instead of the original complex object.
Avoid sending class instances, Maps, Sets, or custom-prototype objects across the server/client boundary unless the framework explicitly supports that type.
