Hi Tuan,
To answer for your question no.2, the red color indicates that the AP has some core files or crash files stored. This is not indicating any service imapct and this is the same symbol with "*" that you could see next to the hostname when you login to the AP.
If you already recognized the crash information, then you can clear it with "service clear crash-info" command after login to the AP, then the red color should disappear after few minutes.
Regards,
David.