System.InvalidOperationException: 'String[n]: the Size property has an invalid size of 0.'

This error occurs generally when we are not passing the Output parameter in the SqlDbType.VarChar value like the below example

SqlParameter job1 = cmd2.Parameters.Add("@job", SqlDbType.VarChar);
job1.Direction = ParameterDirection.Output;

You need to define a length when specifying SqlDbType.VarChar parameter, So

SqlParameter job1 = cmd2.Parameters.Add("@job", SqlDbType.VarChar, 50);

You should use the same length as defined in your SQL Server stored procedure.