Yes it is certificate (or encryption) related.
I've seen lots of this kind of thing lately.

A. Some previously accepted certificate authorities are no longer being accepted (like StrtaSSL).
B. Some servers are not up to snuff to handle the elimination of TLS 1 and 1.1 and being forced to use TLS 1.2
I moved about 30 websites to a newer server last year to avoid this issue.
C. Could be as simple as their cert expired and will be fixed tomorrow. Or they added content not being served securely (browsers no longer handle mixed content in a forgiving way). This can be a simple call for a JQuery script and using http:// instead of https://

If it's a bank, I would think they would notice and respond pretty quickly.

Usually Safari is the first browser with new issues, but Chrome is catching up quickly.


Make your sound your own!
.. I do not work here, but the benefits are still awesome