Referring dll NewtonSoft.Json and System.Data.SqlClient

Good afternoon guys, has anyone had this type of scenario from the prints below?
I referenced the NewtonSoft.Json dll and also the System.Data.SqlClient and both are having problems, in the case of NewtonSoft it can reference within the visual studio but in the unity editor it accuses the reference,… and the Data. SqlClient it references and does not recognize the dll within visual studio.

Has anyone experienced this or know how to fix it? I’ve been in this problem for a long time

I’m using version 2020.3.28f1

I managed to solve the problem, I had to import the dll again,… I’m just having the problem with the Data.SqlClient dll:

Severity code Description Project file line suppression state
Error CS1069 Type name ‘SqlConnection’ not found in namespace ‘System.Data.SqlClient’. This type was forwarded to assembly ‘System.Data, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089’ Consider adding a reference to this assembly. CSharp-mount