It is a known issue as stated in Laravel 5.1 documentation.

    Note: Renaming columns in a table with a enum column is not currently supported.

It happens when you have a enum column in your database table. Whether you are trying to rename another column, or change another column to nullable, this bug will appear. It's an issue with Doctrine\DBAL.

An easy fix for this is to just add this constructor method in your database migration file.

public function __construct()
{
    DB::getDoctrineSchemaManager()->getDatabasePlatform()->registerDoctrineTypeMapping('enum', 'string');
}

This will map all the ENUM columns to VARCHAR(), and the column will accept any string.

    This worked for me on Laravel 5.1 and Laravel 5.3. I hope this bug can be fixed soon.

Credit to @Gmatkowski's answer at https://stackoverflow.com/a/32860409/1193201