Many friends say that they have sent 1,000 emails but there is no effect. The editor can only say that you have not analyzed your own product, the corresponding market of the product, the corresponding purchasing manager, the content of the development letter, etc. If you have not done a specific analysis and just copied and pasted the email, and sent it in bulk, the effect will be so-so. If you send the mass email to a good customer, you can only say that you are lucky.