After trasporting my project from the 2021 version of unity to the 2019.4.40f1 there is one error i cant deal with

This is the error:

Library\PackageCache\com.unity.visualscripting@1.8.0\Runtime\VisualScripting.Core\Serialization\ISerializationDependency.cs(9,23): error CS0106: The modifier ‘internal’ is not valid for this item

I’ve had this issue for 2 days now and i cant fix it… if you have the time to help then that would be perfect…