Hello,

Try add a exception manually:

1. Go to Tools >> Options
2. Advanced >>Certificates >> View Certificates
3. Servers >> Add Exception
4. In Location type the general url, for example, http://youtube.com
5. Click on "Confirm Security Exception"

EDIT: Did you try do these steps with the link that you say that doesnt appear the ssl exception message?

If you use a proxy that creates its own connection to the website and sends you a certificate that is created on the fly then you will have to see if you can find the root certificate of that proxy and install this certificate in the Firefox Certificate Manager.
If you have other browsers that have this proxy root certificate then you can export it there.

Edit: I didn't read carefully enough. Please see cor-el's response regarding the proxy's certificate.

You shouldn't need to add exceptions for major sites, these companies generally have their act together.

There probably is some software on your computer intercepting your secure connections. It may be software you trust and want to be doing this, or it may be malware.

If you have already added exceptions, please look up the issuer on one or two of them to learn more about the source of this issue.

orange Firefox button (or Tools menu) > Options > Advanced > Certificates mini-tab > "View Certificates" button > Servers tab

Click a certificate and use the View button. The kind of issuer you might find is:

• Name associated with your security software, such as ESET, BitDefender, Kaspersky, etc.
• Sendori (indicates unwanted software from Sendori)
• FiddlerRoot (indicates unwanted software named similarly to BrowserSafeguard, BrowserSafe, SafeGuard)
• Something else

(If you haven't added any exceptions, you usually can view the certificate from the Add Exception dialog without adding it.)

@ Diego Victor ...I've try your method but it doesn't work (the page es youtube.com still incomplete)...and when I'll go to add security exception is like the attach image.

@ cor-el I think that I already have the root certificate from the proxy server otherwise I'll not able to surf in internet??..correct??

@ jscher2000 I don't think there is any software on your computer intercepting my secure connections because with other browser (opera,explorer) all is ok. In the general form of the certificate will appera "Could not verify this certificate because the issuer is unknown" In the details form under Issuer submenu there is this: E = support@zscaler.com CN = Zscaler Intermediate Root CA. ST = California C = US

thanks for all!!! ...other suggestion???

Hi dafunk, you probably need to import the root certificate from IE or Opera. Do you have IT department support that can assist?

@ jscher2000

The certificate that I have in Firefox are the same (..much more) of that I have in Opera....I try to import the certificate from IE to Firefox but the issue will persist. If I haven't the root certificate in Firefox may be I'll not able to view any site....but my problem is only for https site...and only with firefox....I'll never request any intervent from my IT support for Opera browser......O_o....any idea??

The problem is that Firefox seems doesn't request the form for the certificate approval in some sities like gmaps or youtube otherwise other browser do that.....;-(

Hi dafunk, yes, only HTTPS sites are affected because Firefox only checks certificates for HTTPS sites.

The root certificate from the proxy service provider allows Firefox to trust all the fake certificates they issue, so that should be the only one your need. I don't know whether it is supposed to be pushed into Firefox automatically, but since it didn't work, importing is your next step.

I found some instructions on how to do it from unofficial sources. Maybe one of these will help?

• How to Install Zscaler SSL Trusted Root Certificates | MCNC | Connecting North Carolina's Future Today
• Orange County Schools
• Bring Your Own Device - Bertie County Schools

VERY IMPORTANT: Do not actually use the certificate supplied by these sites. Only consult them for steps that you might use the install a certificate provided by your IT. Otherwise who know what you're trusting.

@ jscher2000

Thanks so much!!!!!....I've install the certificate from the link you've post (even you told me to don't install them....:-)......)........but now it works!!!!!!