I used QQ e-mail and 163 e-mail to send my resume to the e-mail displayed on the recruitment pages of several companies, but they were all rejected!

Those companies all use corporate mailboxes. An enterprise mailbox with its own company domain name as the suffix. When you send an email to it, it may be that their corporate mailbox is set with anti-spam settings, or the email is full, resulting in the email being rejected. If you want to set up a foxmail client, you must first confirm whether your free mailbox has pop3 permission. Now many free mailboxes don't support clients. Of course, the company email will do. For details, please refer to this FOXMAIL setting:/leaf127 @126/blog/static/1216639720091614953572/