Hi Joyce,
Thank you for posting in Microsoft Community. I'm sorry to hear you're having issues with Outlook, especially after getting Office 365, it’s frustrating when something as basic as sending or receiving emails doesn’t work, and switching back to Classic Outlook didn't fix it.
Issues like this are often caused by outdated software, corrupted profiles, or misconfigured settings. Microsoft recommends using the Support and Recovery Assistant for Microsoft 365, which can automatically detect and fix many common Outlook connectivity issues. If that doesn’t help, checking for updates, recreating your Outlook profile, or reviewing your account setup might be necessary.
Are you using Outlook on Windows, Mac, or through the web? And do you see any error messages when trying to send or receive emails?
You can use this link to contact Microsoft support: https://support.microsoft.com/en-us/contactus/#!
Let me know so I can help you more. I will be more than happy to assist you.
Regards,
Carlo