How can I fix the Unity compiler error in version 2019?

Question

My unity game engine has this problem .How can I fix this problem. It is very necessary

Microsoft (R) Visual C# Compiler version 2.9.1.65535 (9d34608e) Copyright (C) Microsoft Corporation. All rights reserved.

error CS1703: Multiple assemblies with equivalent identity have been imported: 'C:\Users\Graphend\Documents\TestUnity\Assets\Plugins\System.Web.dll' and 'C:\Program Files\Unity\Editor\Data\NetStandard\compat\2.0.0\shims\netfx\System.Web.dll'. Remove one of the duplicate references.

Answer 1

try to remove the one in Graphend\Documents\TestUnity\ but before removing save it somewhere, so that u might turn it back