Was fiddling with email from my health insurance company that came "secure" via #Cisco secure email of some sort. I followed all the instructions and could not get it to open. Finally, tried Chrome and it worked. So the problem appeared to be some compatibility w Cisco's system of encryption/authentication and #Firefox. I googled it, and found this: https://www.cisco.com/c/en/us/td/docs/security/email_encryption/CRES/recipient_guide/b_Recipient/b_Recipient_chapter_0101.pdf
Scroll down and you'll find that in order to use the thing, you have to turn on cross site scripting.
