Some organizations and companies using Office 365 restrict 3rd-party applications like Astro. Apps are restricted during authentication or through Mobile Device Management (MDM) policies.
If this is the case, you may see these pages when trying to add your account:
If you see these screens, please ask your company's Office 365 administrator to create an exception for Astro by providing consent for our app to work within Office 365. Some companies may not be willing to make exceptions, in this case you won't be able to use Astro with your Office 365 account.