Should I stop contacting a lead after one no?

There are two different situations here, and they get opposite answers. If someone tells you no or asks you not to contact them, stop immediately. No clever workarounds, no one last message. Respecting a no protects your reputation and keeps you on the right side of the rules. But silence is not a no. If they simply have not responded, respectful follow-up continues. Most people confuse these two, quit on the silent ones, and leave real conversations on the table.