Outlook attachment preview stops working after a few minutes from Web based Outlook

Hi, I have this ongoing issue with one of our users. It just occurred one day wherein the preview of attachment stops working for a few minutes using web based Outlook O365. When he close and re-open the browser, it will work for a few minutes again (within 30 minutes of usage). User both tried it on Chromium and Chrome same issue. 

Steps we tried:

Reset both browsers

Downloaded Office 365 updates

Made sure Attachment preview not disabled under Outlook Client

Did download Win 10 updates as well

Check Win defender settings

All of these steps didn't help. User prefers to use webmail instead of the client thus I want to check if anyone had encountered the same issue and what helped to resolve the problem.