Hi TinManXVL, where are you seeing this address?

The SafeBrowse.io domain is registered to Comcast. If you use Comcast/Xfinity, this could be associated with one of their security features.

Google Safe Browsing

Firefox's Phishing and Malware protection feature using data from the Google Safe Browsing project (along with various other browsers; https://safebrowsing.google.com/). Firefox regularly checks for updates to the lists of dangerous sites; that is normal. More info:

• How does built-in Phishing and Malware Protection work?
• How to stop Firefox from making automatic connections

I see it in the address bar. Yes They are my isp. That and on some websites I have been getting a "too many requests" message. I will contact Comcast and see as well. Thank you. Not resolved but a good start.

You can try these steps in case of issues with web pages:

You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• hold down the Shift key and left-click the Reload button
• press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• press "Command + Shift + R" (Mac)

Clear the Cache and remove the Cookies for websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences).

"Remove the Cookies" for websites that cause problems:

• Options/Preferences -> Privacy & Security
  Cookies and Site Data: "Manage Data"

"Clear the Cache":

• Options/Preferences -> Privacy & Security
  Cookies and Site Data -> Clear Data -> Cached Web Content: Clear

Start Firefox in Safe Mode to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if hardware acceleration is causing the problem.

• switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Themes
• do NOT click the "Refresh Firefox" button on the Safe Mode start window

• https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode
• https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems