Avast pops-up with this warning when using changeip.com website:
“Avast web shield has blocked access to this page because the following certificate has been revoked: *.changeip.com”
It doesn’t actually stop access to the site.
I asked about this on the changeip.com forums, they said there isn’t a problem.
https://forum.changeip.com/forum/general-discussion/301-avast-warning-about-changeip-com
EDIT: Free version 2015.10.2.2218