why an i being blocked from sites using youtube?
Did Not Connect: Potential Security Issue
Firefox detected a potential security threat and did not continue to www.youtube.com because this website requires a secure connection.
What can you do about it?
www.youtube.com has a security policy called HTTP Strict Transport Security (HSTS), which means that Firefox can only connect to it securely. You can’t add an exception to visit this site.
The issue is most likely with the website, and there is nothing you can do to resolve it.
If you are on a corporate network or using anti-virus software, you can reach out to the support teams for assistance. You can also notify the website’s administrator about the problem.
if your work network is blocking https and trying to force you to load http version it might be running into this.
Would you try this please :
Type in the address bar about:config and press Enter (ignore the warning)
Type in the search bar and look for the preference :
and change its value from "false" to true.
Then close and restart Firefox.
Does that make a difference ?