So this is not a browser issue, just email missing? Is this in Thunderbird? Who is you email provider?

Just emails disappeared suddenly. not in Thunderbird. Email provider is Outlook

Do you see this option in Outlook? see screenshot If not, then you will have to contact Outlook support.

https://answers.microsoft.com/en-us

No I didn't. Outlook help is difficult to find. Can you tell me how?

Click on my link and then you will see the option to ask a question. see screenshot

Also, mark this issue as resolved on your way out the door.  ;-))