There are two possible reasons

1. Not specifying or In correct csrf token in Ajax Requests: Note It is
important that your token is passed as X-CSRF-TOKEN. All in caps else Laravel
will keep throwing the 419 error.

2. Session expired error due to cache: Sometimes, the cache can also lead to
session expired error in front-end. This can be both the server cache and
browser cache. To fix, clear cache or increase its time