Outlook.live.com webmail not showing any emails or folders

I've had a Microsoft 365 account for several years.

I've been using the Outlook apps on my desktop and phone, and they work fine.

The only email account I use is a gmail account.

I logged into the webmail page to create a rule.

I signed in successfully with my gmail address.

The only email message is a "Welcome to your new Outlook.com account." from five years ago.

No other messages or custom folders.

I tried sending a message to another email, and it was received. 

The sender name is "My Name <email address removed for privacy reasons>", no clue what that is.

I tried replying and it bounced back "PPE Hosted tried to deliver your email message, but was unable to do so for reasons outside our control".

How can I get my webmail to work properly?