Thomas,
Hi,
I can't believe I am the first one reporting but in case I am:
The certificated of https://lists.amavis.org/ expired on Saturday,
April 25, 2015. The current date is Saturday, January 16, 2016.
That's a huge problem because you have enabled HTTP Strict Transport
Security (HSTS) for this site with the result that no HSTS-supporting
browser is currently able to access the amavis ML archive.
Fixed today by Ralf, thanks for a report and for a fix!
Sorry to have enabled HSTS for domain amavis.org without considering
lists.amavis.org. Should be fine now, we are all at Let's Encrypt
certificates with automatic renewals.
Mark