The Django project cannot send mail after deploying the ECS

The problem background ：Django When the project deploys Alibaba cloud and Tencent cloud servers, it cannot send mail , But deploying to Baidu cloud server can . Later, I found that Baidu cloud server was turned on by default 25 port , The ECS of Alibaba cloud and Tencent cloud are turned off by default . Here is Tencent cloud open 25 Method of port ：

step 1： Log in to Tencent cloud console

step 2： Click on the top right picture 》 security management 》25 Port unsealed 》 apply 25 Port unsealed

step 3: Select the server to unseal