how to remove ad.doubleclick.net on my safari?

What you're seeing in your screenshot is the result of the server (in this case ad.doubleclick.net) requesting the client (your computer) also authenticate itself during the TLS handshake (a secure encrypted communication session, like HTTPS). This is a valid response to a completely valid request. The problem is that, we aren't accustomed to websites in general requiring us to authenticate ourselves using SSL certificates, Client Authenticated TLS is not commonly used. Its understandable that a lot of you are being thrown off by the request shown in the screenshot.

I've also noticed this issue using Chrome on Android, and have seen reports online of the issue showing up in Chrome under Windows as well. So, this is not an Apple specific issue. At least not based on what I'm seeing in your screenshot, because I can reproduce that. I have no idea what op is talking about removing ad.doubleclick.net.

Which brings me to my next point. There's a lot of FUD in here about what DoubleClick is, its not malware, well not specifically. DoubleClick is one of Google's ad platforms. It's that service that websites use to serve up banner ads on their pages.

All in all, this issue is probably due to a recent screw up over at DoubleClick, it wouldn't be the first time and it will probably sort itself out. So take your fingers off the Option, Command (⌘), P, and R keys or whatever other voodoo you were planning and just click cancel when this prompt appears, it's harmless ;-) But don't click Continue, we don't need to give the ad-men yet another way to identify us do we?

ok... so this is working for me at the current moment. I went to Library>internet plug-ins and deleted whatever crap was in there and poof! running now for about 10 minutes with great success. will be sure to keep everyone posted.

ok... so this is working for me at the current moment. I went to Library>internet plug-ins and deleted whatever crap was in there and poof! running now for about 10 minutes with great success. will be sure to keep everyone posted.

sorry for the multiples it wouldnt let me send... 😠

I think your reflections are correct.

It's not really a virus. I have the suite of Intego tools running, including Virus Barrier, and it found nothing.

I haven't changed anything about the way I'm operating, and like others here have reported, suddenly this certificate validation starts popping up.

Press cancel, and it goes away, and comes back. But today, thankfully it's not doing it. Maybe it's over.

Someone at the ad tracking company must have re-figured out how to get our computers to validate with them and do their tracking without asking us.

Same thing for me. Yesterday Dec 10th 2015, nothing appears on my screen. It did stop actually.

Thanks for your explanation, I understand what's happening much clearer now.

Thankfully, the validation pop up has disappeared as mysteriously as it began.

The "Delete the "doubleclick" cookie from Safari Pref and done the press the shift key while open Safari " solution worked for me. Thanks !