Can you attach a screenshot? *https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem *use a compressed image type like PNG or JPG to save the screenshot Is that the red phishing protection page? *https://support.mozilla.org/en-US/kb/how-does-phishing-and-malware-protection-work You can do a malware scan just to be sure. *https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware