I can do a delete, insert and update in my program and I try to do an insert by call a created stored procedure from my database.
This a button insert I make work
As an alternative, I have a library that makes it easy to work with procs: https://www.nuget.org/packages/SprocMapper/
SqlServerAccess sqlAccess = new SqlServerAccess("your connection string");
sqlAccess.Procedure()
.AddSqlParameter("@FirstName", SqlDbType.VarChar, txtFirstName.Text)
.AddSqlParameter("@FirstName", SqlDbType.VarChar, txtLastName.Text)
.ExecuteNonQuery("StoredProcedureName");