You will need to remove your current Canisius account.
You will then add a mail account.
tap Continue at lower right
iOS: a screen will appear with your email address filled in and a password field; below that is a slider button for Advanced Settings; tap it to see the additional fields required
fill out next screen as follows:
password: your canisius password
description: user choice (e.g. Canisius)
tap checkbox in upper right
The screenshot below is from an Android 9 device: