Cannot convert null literal to non-nullable reference type.

'Rfc2898DeriveBytes.Rfc2898DeriveBytes(string, byte[], int)' is obsolete: 'The default hash algorithm and iteration counts in Rfc2898DeriveBytes constructors are outdated and insecure. Use a constructor that accepts the hash algorithm and the number of iterations.' (https://aka.ms/dotnet-warnings/SYSLIB0041)

'RijndaelManaged' is obsolete: 'The Rijndael and RijndaelManaged types are obsolete. Use Aes instead.' (https://aka.ms/dotnet-warnings/SYSLIB0022)

'RijndaelManaged' is obsolete: 'The Rijndael and RijndaelManaged types are obsolete. Use Aes instead.' (https://aka.ms/dotnet-warnings/SYSLIB0022)

Cannot convert null literal to non-nullable reference type.

Cannot convert null literal to non-nullable reference type.

Non-nullable property 'Body' must contain a non-null value when exiting constructor. Consider declaring the property as nullable.

Non-nullable property 'InnerException' must contain a non-null value when exiting constructor. Consider declaring the property as nullable.

Cannot convert null literal to non-nullable reference type.