@dkmackie
Basically, if the app is not able to guess the right server settings, please tap the Manual button (after entering your email and password) and you'll be able to enter them yourself.
If in doubt, please ask your company's IT people:
- Whether the corporate server supports EWS (Exchange Web Services), this is what Aqua Mail uses to connect to Exchange.
An official part of Exchange since 2007, should be enabled by default, but sometimes is disabled for various reason.
- If it is enabled, what the server settings are (server name is the most important).
For Office 365 (even if it's under your company's domain), please use server name outlook.office365.com (and the rest is default, SSL encryption, port 443).