User demo not working and config:cache clear problem

[mkamranmalik72]

I am installed new lavalite, admin and client demos are working well but when I access /user its shows following error:

also, I am getting one more error when I run command PHP artisan config: cache getting following error:
In ConfigCacheCommand.php line 71:

Your configuration files are not serializable.

In config.php line 2267:

Call to undefined method Illuminate\Validation\Rules\In::__set_state()
kindly solve this asap please