Mail Inbox from Mail Server are moved to ERPNext Inbox

Hi, i have created a domain and created an email account based on that domain. Then i have linked the email account to a user. Now, when i checked the mail inbox in the server inbox, there are no mail there and everything have been moved to ERPNext, the domain use webmail service.

But when i created a Gmail email account, the inbox mails are still there on the gmail inbox. So how can i moved all the inbox mails in ERPNExt back to my webmail inbox?