
Here is a line from httperr.log: 18:44:52 x.x.x.x 27313 74. the ERR_CONNECTION_TIMED_OUT Error Update again: It appears to be a somewhat intermittent problem, however it is back at this time, though it looks like maybe it is IPv4 not working and IPv6 working this time around. They were all showing the same behavior earlier, but now have mysteriously corrected themselves. I had run tests in both Chrome and Firefox from both Windows machines and Android from 4 different devices with 4 different internet connections in 2 different states. Update: It appears whatever was causing the problem resolved itself. Attempting to use the IPv6 address for with one of the other sites had the same failure (moved the binding to another IIS site). Other sites on the same IIS instance but using different IPv6 addresses and IIS sites are working fine.

I have rebuilt the bindings without any luck. When connecting to the hostname with no subdomain or when connecting to another domain bound to the same site, IPv6 works fine, however when attempting to connect with a Both working and unworking bindings are going to the same IPv6 addresses and both the working IPv4 bindings and the IPv6 bindings are on the same IIS site. When connecting from the server via IPv6 or connecting from any system via IPv4, everything works fine and the site loads as expected.

Running IIS 10 on Windows Server 2016, I have encountered an issue where an IPv6 binding has mysteriously stopped working.
