invalid security certificate - addthiscdn.com

[#1]

PlusNet
FYI my Firefox just flashed me an invalid certificate message whilst accessing a PlusNet community page:
l.addthiscdn.com:443 uses invalid security certificate - Certificate only valid for
DNS Name: *.addthisedge.com
DNS Name: addthisedge.com
DNS Name: *.addthis.com
DNS Name: addthis.com
CN = *.addthisedge.com
OU = Operations
O = "Clearspring Technologies, Inc."
L = McLean
ST = Virginia
C = US

Maybe just a glitch at their end???

[#2]

That's been noted before when accessing the service status page, but I will only see the invalid certificate message if I open the Error Console and look for it.