Hello and welcome to Apple Support Communities, MyFriendJack81,
If we understand your post correctly, you're getting an error when you try to add your Outlook account to iOS Mail but you're able to sign in with the same information on the web. We’d like to help.
Please make sure you're following these steps to add your account: Add an email account to your iPhone, iPad, or iPod touch - Apple Support
"How to set up your email account automatically
1. 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:
2. Go to Settings > Mail, then tap Accounts.
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."
If you're still unable to add your account we'd recommend contacting Apple Support directly. You can do that here: Contact Apple Support
Thanks for using the Apple Support Communities.