I have noticed a peculiar quirk in my Opera Mail (ver. 1 running under Windows 8.1) if it is open when my computer goes into sleep mode after a period of inactivity.
When the computer wakes up, there is an orange triangle with an exclamation mark beside the Inbox in the left navigation pane and no new email will be downloaded from my Gmail account until I close Opera Mail and then reopen it.
Any suggestions on how to fix this?