https://www.identrustssl.com/ https://www.identrustssl.com/ authenticates fine for me in both Firefox and Chrome, and the certificate issuers for both that site

https://www.identrustssl.com/ https://www.identrustssl.com/ authenticates fine for me in both Firefox and Chrome, and the certificate issuers for both that site and https://letsencrypt.org/ https://letsencrypt.org/ is in fact the same. I did notice that the IdentTrustSSL certificate has been issued yesterday, so this might be an issue of wrong clocks on your end.