[asterisk-users] Suddenly getting lots of "Unable to send packet: Address Family mismatch between source/destination" but ONLY on 1 of 2 VPSs in same datacentre.

[Jonathan H]

Two VPSs. Identical setups with the exception of the extension.

Same version of everything, Asterisk 14.1, Ubuntu 16.10, same firewall
rules and so on -  box 2 was cloned from box 1.

Both VPSs run in the same datacentre.

Suddenly, after weeks of OK, I'm getting lots of this on ONE box only:

[Nov  4 21:23:04] NOTICE[1468]: res_hep.c:466 hep_queue_cb: Unable to
send packet: Address Family mismatch between source/destination
[Nov  4 21:23:04] NOTICE[1468]: res_hep.c:466 hep_queue_cb: Unable to
send packet: Address Family mismatch between source/destination

Googling this brings up something about IPv6, but my VPS is not IPv6
enabled, and nor is my ITSP, who can't think of why this is happening.

It doesn't appear to be adversely affecting call quality, but it's
making the console a bit busy. I know I can hide it, but I'd be
interested to know if there's anything I can do to diagnose WHY this
is happening.

Thanks