I already have {{ csrf_field() }} in form. it works fine but after inactivity for some time create this error. why ?
You should change lifetime of your session so that CSRF token could stick around longer. It is set up in config/session.php
file, by default it's configured as:
'lifetime' => env('SESSION_LIFETIME', 120),
Meaning your session will persist for 120 minutes by default if not set otherwise in your .env
file.