Access the Business Mailboxes section in your account.

This can be done in 2 ways: 

1. Going to the Manage cPanel / Manage Managed WordPress section in your account. Click on the Manage dropdown menu and select Mailboxes. 
2. Going to Manage Add-ons then to Business Mailboxes section in your main Heart Internet control panel.    

In there, next to the mailbox, you will have a “Change” button under the Password column. Once pressed, you will be prompted to enter the new password for the mailbox.

Once updated, it will take 5-10 minutes for the new password to sync. You can check if the correct password was added by trying to access the mailbox via Webmail at https://webmail.heartinternet.uk/login/