SerializableClosure error in Laravel - Your serialized closure might have been modified and it's unsafe to be unserialized

What solved it for me was running the following in my project folder:

php artisan route:clear

I also ran the below commands before the above command, but the error persisted. It only went away when I did the above. For reference, here are the commands I ran beforehand:

php artisan cache:clear
php artisan config:clear
php artisan view:clear
npm run dev
php artisan key:generate

I also want to note that I am using the following stack:

Laravel v8
Jetstream
Inertia
Vue2

This issue might occur due to change in APP_KEY value in your .env file.

APP_KEY is used for secure data transmission and Laravel recommends to do that by setting it to a random string.

This APP_KEY is used for

• Encrypting cookies.
• Creating the signature for signed URLs and queued closures.
• Encrypting values using the encrypt() and decrypt() helpers.

A encrypted data can be decrypted if you use the same key which was used while encrypting.

So if possible look for a backup .env file and use the same APP_KEY to resolve it.

It happened to me when I replaced in production my .env file with the .env from development. It was failing because it had a different APP_KEY, so I had to generate a new APP_KEY on production.

It was solved after run these commands:

php artisan key:generate
php artisan config:cache
php artisan route:cache
php artisan view:cache

Maybe it isn't necessary to clear the views and routes.

try this command

 composer update

In vendor → .env,

change APP_URL to http://localhost.