Loss of email on several Apple devices

Thank you for the reply tlfmd. We want to clarify something you just advised. You mention deleting the account from "the Outlook app". Are you stating that you use the Outlook app for this email account and not the Apple Mail app?

If so, to further narrow down if the issue is app-specific or your overall iOS, we'd recommend trying to add that account through our steps with Mail.

Add an email account to your iPhone, iPad, or iPod touch - Apple Support

If you can add the account to use through the Mail app, the issue would be specific to the Outlook app. We'd recommend contacting their app developer from that point if you wish to continuing using their app for your email account.

How to contact an app developer - Apple Support

Take care.

Hi tlfmd,

Thanks for posting in Apple Support Communities.

It sounds like you're unable to use an email account that was removed by your email service provider and you need to add it back.

"How to set up your email account automatically

If you use an email provider like iCloud, Google, or Yahoo, Mail can automatically set up your email account with just your email address and password. Here's how:

1. Go to Settings > Mail, then tap Accounts.
2. 
3. Tap Add Account, then select your email provider.
4. Enter your email address and password.
5. If you see Next, tap Next and wait for Mail to verify your account.
6. If you see Save, tap Save.

If you don't see your email provider, tap Other to add your account manually."

Add an email account to your iPhone, iPad, or iPod touch - Apple Support

Regards.

Hey tlfmd,

We'd recommend contacting Apple Support for further assistance here: Get Support

Thanks!