Extension not getting installed through composer in cpanel - yii2

Question

I am using yii2 basic application template. I have VPS server for hosting my software. In my cpanel I have installed composer successfully. Then I uploaded my files from local machine to the server.
Now I want to do composer update in cpanel using Putty.
My composer is as below:
{
"name": "yiisoft/yii2-app-basic",
"description": "Yii 2 Basic Project Template",
"keywords": ["yii2", "framework", "basic", "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": ">=5.4.0",
"yiisoft/yii2": ">=2.0.5",
"yiisoft/yii2-bootstrap": "*",
"yiisoft/yii2-swiftmailer": "*",
"nex/yii2-datepicker": "*",
"kartik-v/yii2-mpdf": "*",
"wbraganca/yii2-dynamicform": "*",
"yiisoft/yii2-jui": "#dev",
"bupy7/yii2-dynamic-fields": "*",
"unclead/yii2-multiple-input": "v2.9.0",
"faryshta/yii2-disable-submit-buttons": "#dev",
"phpoffice/phpexcel": "#dev",
"mdmsoft/yii2-admin": "*"
},
"require-dev": {
"codeception/codeception": "*",
"yiisoft/yii2-debug": "*",
"yiisoft/yii2-gii": "*",
"yiisoft/yii2-faker": "*"
},
"config": {
"process-timeout": 1800
},
"scripts": {
"post-create-project-cmd": [
"yii\\composer\\Installer::postCreateProject"
]
},
"extra": {
"yii\\composer\\Installer::postCreateProject": {
"setPermission": [
{
"runtime": "0777",
"web/assets": "0777",
"yii": "0755"
}
],
"generateCookieValidationKey": [
"config/web.php"
]
},
"asset-installer-paths": {
"npm-asset-library": "vendor/npm",
"bower-asset-library": "vendor/bower"
}
}
}
Everything is fine, when I type the command composer update, it shows the below error
[ifsoftware1234#216-10-245-56 basic]$ composer update
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.
Problem 1
- Installation request for nex/yii2-datepicker * -> satisfiable by nex/yii2-datepicker[dev-master].
- nex/yii2-datepicker dev-master requires bower-asset/eonasdan-bootstrap-datetimepicker 4.17.* -> no matching package found.
Potential causes:
- A typo in the package name
- The package is not available in a stable-enough version according to your minimum-stability setting
see <https://getcomposer.org/doc/04-schema.md#minimum-stability> for more details.
- It's a private package and you forgot to add a custom repository to find it
Read <https://getcomposer.org/doc/articles/troubleshooting.md> for further common problems.