class_exists(): Passing null to parameter #1 ($class) of type string is deprecated – Docker

I had this newly installed Yii2 advanced and want to know if anyone of you ever encountered this error after login from the frontend?

What solution did you do to solve this issue?

Below is my composer.json

{
    "name": "yiisoft/yii2-app-advanced",
    "description": "Yii 2 Advanced Project Template",
    "keywords": ["yii2", "framework", "advanced", "project template"],
    "homepage": "http://www.yiiframework.com/",
    "type": "project",
    "license": "BSD-3-Clause",
    "support": {
        "issues": "https://github.com/yiisoft/yii2/issues?state=open",
        "forum": "http://www.yiiframework.com/forum/",
        "wiki": "http://www.yiiframework.com/wiki/",
        "irc": "irc://irc.freenode.net/yii",
        "source": "https://github.com/yiisoft/yii2"
    },
    "minimum-stability": "stable",
    "require": {
        "php": ">=5.6.0",
        "yiisoft/yii2": "~2.0.14",
        "yiisoft/yii2-bootstrap4": "~2.0.0",
        "yiisoft/yii2-swiftmailer": "~2.0.0 || ~2.1.0"
    },
    "require-dev": {
        "yiisoft/yii2-debug": "~2.1.0",
        "yiisoft/yii2-gii": "~2.2.0",
        "yiisoft/yii2-faker": "~2.0.0",
        "codeception/codeception": "^4.0",
        "codeception/module-asserts": "^1.0",
        "codeception/module-yii2": "^1.0",
        "codeception/module-filesystem": "^1.0",
        "codeception/verify": "~0.5.0 || ~1.1.0",
        "symfony/browser-kit": ">=2.7 <=4.2.4"
    },
    "config": {
        "process-timeout": 1800,
        "fxp-asset": {
            "enabled": false
        }
    },
    "repositories": [
        {
            "type": "composer",
            "url": "https://asset-packagist.org"
        }
    ]
}