Gmail can not verify mails from oracle.com anymore.

[Volker Simonis]

Hi,

I've subscribed to most Openjdk mailing lists from my Google mail
account (gmail.com).

Today I noticed that all mails in my inbox which were sent from the
oracle.com domain are flagged with "Gmail couldn't verify that
oracle.com actually sent this message (and not a spammer)". Clicking
on the message redirects me to the following goolge site about email
authentication:

https://support.google.com/mail/answer/180707?hl=en

I also get this warning for older messages in my inbox for which I
definitely didn't got it at the time when I received and read the
corresponding messages for the first time.

Has anybody else noticed this behavior? Does anybody know if this is
caused by problems on Google's or on Oracle's site.

I'm concerned that I will miss mails because they can be classified as
spam and moved into the spam folder by default.

Regards,
Volker