not able to install your plugin

[Kalpeshpatelbyk]

LogicException : Unable to prepare route [api/user] for serialization. Uses Closure.

at C:\xampp\htdocs\Jni\vendor\laravel\framework\src\Illuminate\Routing\Route.php:917
913| */
914| public function prepareForSerialization()
915| {
916| if ($this->action['uses'] instanceof Closure) {

917| throw new LogicException("Unable to prepare route [{$this->uri}] for serialization. Uses Closure.");
918| }
919|
920| $this->compileRoute();
921|

Exception trac

[makermyke]

Same here. Any solution for this?
I am using Laravel 7, not sure if this is compatible with Webpatser.