Sometimes after changing your password, your mobile phone's built-in email application will keep prompting for your new password, but it doesn't accept it when you type it in. It either gives you an error, or keeps prompting without an error.
Officially, OTC suggests downloading and using the Outlook application from your device's app store, typically the Google Play store for Android devices, or the Apple App Store for iOS devices. The Outlook app has superior compatibility with Office 365 services and is less likely to run into this issue.
However, we have found that removing your OTC email account from your device and then re-adding it to your device will sometimes get your email working again in your device's built-in application. Instructions for how to do this vary greatly depending on your version of Android or iOS, but you can drop by your phone's carrier store for assistance. OTC does not provide support for the built-in app.
Known issue: There is a known problem with passwords updating when you have the Microsoft Authenticator App on your mobile device and you are using other Office 356 apps (e.g. Outlook, Teams) with the same account on that device. If you change your OTC password and you have already authenticated your account that day using the Microsoft Authenticator App, your new password may not be able to update on your other Microsoft mobile apps until the next authentication cycle (up to 24 hours). The best solution in this case is to remove your OTC email account from your device, and then re-add it.