Hello, thank you for reaching out to Microsoft Q&A.
Open an incognito tab on any web browser and sign in with your Microsoft account here-
Let me know if you are still unable to see any emails in the Outlook web version.
Also, try clearing your browsing history, cache, and cookies. Then switch to another browser or network and check whether you can see your emails in the Outlook web version.
If you have not been receiving any new emails for the past month, make sure you have enough storage in your Microsoft account to send and receive new emails.
https://outlook.live.com/mail/0/options/accounts-category/storage