Lolipop by GMO cloud is the hosting service I’m using. The hosting plan includes email hosting services, but the webmail interface is in Japanese with limited functions provided, so I installed my own Roundcube instance instead. Not like VPS, Installing a custom Webmail service needs to skim through the service provider’s documentation, undoubtedly it is all in Japanese. This takes me some time to search and validate all these endpoints. Anyway, the tutorial is as follows.