This post shows you one of the possibilities your SSIS cannot load the Microsoft.SharePoint.Client dll.
When you wanted to connect to SharePoint Online in your SSIS project then you copied Microsoft.SharePoint.Client and Microsoft.SharePoint.Client.Runtime to a folder and point your Script Component code to it. You have gotten the following error when running it.
“Couild not load file or assembly ‘Microsoft.SharePoint.Client, Version=126.96.36.199, Culture=neutral, PublicKeyToken=71e9bce111e9429c’ or one of its dependencies. The system cannot find the file specified.”
You cannot just copy the dll files to a folder and refer to it. You need to install the SharePoint SDK. The SDK for SharePoint 2016 as below.
Install SharePoint Server 2016 Client Components SDK, https://www.microsoft.com/en-us/download/confirmation.aspx?id=51679.