All Inbox emails are marked as read automatically

All Inbox emails are marked as read automatically

Dear whom it may concern,

My inbox has not been shown unread emails recently and the emails were marked read. Other sub folders are totally fine. I also checked these things and still not found out what the reason is:
  • Filter: No filter
  • Switch to Zoho Mail on Web version
Would you mind to let me know what I can do for this kind of problem?

Rgds,