Why I cannot add hotmail into IPad?

You would be well advised to remove the account entirely from your iPad - then restart the iPad

After restarting the iPad, attempt to re-add the Microsoft Hotmail account - but instead of trying to manually configure account settings, allow the account set-up Wizard to configure the account for you.

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

cindysk_khor wrote:

Errors message “incorrect imap-mail.outlook.com”.

iPhone don’t have problem to connect hotmail but iPad cannot connect at all.

Contact hotmail resolve the issue or look at their support site, since their address is incorrect.