Composer in proxy mode does not working

[alireza11048]

I am receiving the below 404 error when trying to download the package through composer plugin in proxy mode, as you can see in the below:

$composer require mpdf/mpdf
Do not run Composer as root/super user! See https://getcomposer.org/root for details
Continue as root/super user [yes]? y
Composer could not detect the root package (laravel/laravel) version, defaulting to '1.0.0'. See https://getcomposer.org/root-version
Warning: Accessing nexus.afzar.ir over http which is an insecure protocol.
Cannot use mpdf/mpdf's latest version v8.2.3 as it requires ext-gd * which is missing from your platform.
./composer.json has been updated
Composer could not detect the root package (laravel/laravel) version, defaulting to '1.0.0'. See https://getcomposer.org/root-version
Running composer update mpdf/mpdf
Loading composer repositories with package information
Warning: Accessing nexus.afzar.ir over http which is an insecure protocol.
Updating dependencies
Nothing to modify in lock file
Installing dependencies from lock file (including require-dev)
Package operations: 2 installs, 0 updates, 0 removals

• Downloading setasign/fpdi (1.6.2)
• Downloading mpdf/mpdf (v6.1.3)
  2/2 [============================] 100%
  In CurlDownloader.php line 647:

The "http://nexus.afzar.ir/repository/composer/mpdf/mpdf/v6.1.3/mpdf-mpdf-v6.1.3.zip" file could not be downloaded (HTTP/1.1 404 Not Found)

any idea to solve the problem is appreciated.