An IMAP account which can accept connections over SSL/TLS from a third party app. If you are running under a 2-way factor authenticator, you need to disable it or need app password.
Make sure that the Cron of RISE is activated in your server. You can setup cron from Settings > App Settings > Cron Job. Check how to setup Cron job in cPanel.
You wont be able to use IMAP functionalities under a POP account. Make sure that your account is an IMAP-based one.
This plugin has made in order to be able to view/respond to all incoming emails, within RISE CRM. Sent emails from this plugin will be stored into your Sent folder, but actions like Star/Trash/Important will affect your local emails (RISE CRM) only and they will be stored in the database, along with their attachments in the appropriate folder. This plugin has no control over your IMAP server and it is not a two-way sync plugin, it will fetch your unread Inbox emails only.