Using Outlook for Android in business environments for email and scheduling
Hi there! This is Raech. I'm an Outlook.com user like you and I'm happy to help.
Try resetting your account first and see if it helps with the issue. In your Outlook settings page, select your email account under 'Email Accounts' and tap Reset Account.
If that still fails to resolve the issue, delete the account from the app instead and then re-add it. To do this, go back to Settings, select your account and tap Delete Account. You can immediately re-add the account after.
Let me know if any of these helps.