在做了大量的调试问题后，确定为...

它是网络的防火墙，不允许上传多个文件。

当我尝试从不同网络上传文件时，它工作正常。
所以这不是服务器或代码问题。

网络的网络管理员可以修复此错误。

Html code

<form action="projectOperations.php" enctype="multipart/form-data" method="post">
    Upload 1 <input type="file" name="file1"><br>       
    Upload 2 <input type="file" name="file2">   <br>    
    Upload 3 <input type="file" name="file3">       <br>
    Upload 4 <input type="file" name="file4">       <br>
    <input type="submit" value="Submit">
</form>

Php code for projectOperations.php

`var_dump($_POST);`

When i look into console that status still pending

I am using Amazon EC2 instance for this code.

Found two links on stack overflow relevant to this, but no solution found

uploading files stuck on pending

Form having more than one file input not submitted

Can anyone help to understand the problem?

If it server problem what setting i have to change ?

After doing lots of debugging problem was identified as...

It was firewall of network, which was not allowing to upload multiple files.

When I tried to upload files from different network, it worked. So it was not server or code problem.

Network administrator of the network can fix this error.