With a "Server not found" error, you cannot use the Page Info dialog to call up permissions for that server.

With a connection error, hmm, can you give the URL of the page you are trying to open?

What permission did you want to modify?? There isn't a permission setting related to whether Firefox accepts or rejects a site's SSL certificate.

Sorry thought I had included this. http://cfint.rtpnc.epa.gov/otop/biacoe/kb.cfm After I have entered the URL and hit the "go" button the "http://" part of the address disappears.

It's normal for Firefox not to show http in the address bar. It shows the other protocols (e.g., https) so you notice the difference.

I assume you have the same problem in Edge or other browsers on your system.

When I use an online utility to check whether there is an IP address assigned to that server, it doesn't find one:

; <<>> DiG 9 <<>> @localhost cfint.rtpnc.epa.gov A
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 16177
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0

;; QUESTION SECTION:
;cfint.rtpnc.epa.gov.		IN	A

;; AUTHORITY SECTION:
rtpnc.epa.gov.		600	IN	SOA	ying.epa.gov. dnsadmin.epa.gov. 1398457706 3600 900 1209600 600

;; Query time: 629 msec
;; SERVER: 127.0.0.1#53(127.0.0.1)
;; WHEN: Mon Jul 25 01:53:53 2016
;; MSG SIZE  rcvd: 87

It could be they moved its content, took it offline temporarily, or someone made a configuration error and needs to get a heads up. Or it could be that it's not publicly accessible and requires using a VPN or other authenticated method to access the server.

Thanks. I understand most of what you said. You are right it did not work on other browsers either. I did notify the send (I am on an EPA mailing list). He said it worked fine for him (an EPA contractor). I expect it is what you say, it is not available to the public. I appreciate your looking into it for me. Thanks, RAR