Emails not showing up unread

Emails not showing up unread

I put a vacation reply on my email on Friday and since then all new email that arrives is not showing up in bold as unread.

I've removed the vacation reply, logged out and logged in and it's still not happening. It does say "1 unread email" or whatever, but the actual emails are not bold so you don't notice them.

Anyone else having this issue? How can it be fixed?

Thanks

Jon