Firefox doesn't accept Sberbank certificate?

Question

Digital certificates

The search found a note in the GiNeR's Blog dated 06/21/2011.
But there the problem was solved.
Did Sberbank break something or Firefox or my Firefox settings?
It's ok through IE.

Answer 1

online.sberbank.ru uses an invalid security certificate.
The certificate is not trusted because the issuer's certificate chain is missing.

Sberbank broke something.
The certificate is valid from 12/09/2014, apparently, they just changed it and messed up during the reconfiguration (namely, they did not indicate this very chain of the publisher's certificates).

Answer 2

Firefox uses its own trusted root certificate store. Sberbank most likely did not include an intermediate certificate to the required trusted CA in the package of certificates sent at the time the connection was established.

Answer 3

They seem to have rolled back the certificate.
Most likely, their certificate at the time you entered banking _yet_ was not valid (certificates have a "not earlier" field) due to the fact that their system administrators need to be beaten with pissing rags for not knowing about this field and about different time zones.