[tor-relays] ORPort is unavailable after a couple of minutes of successful self-testing

[Tachkov Sergey]

Hello,

We have previously set up and adjusted a non-exit node with the following key parameters:

ORPort 443 NoListen
ORPort 127.0.0.1:4443 NoAdvertise

After upgrading tor up to the latest version (0.2.4.21) we started receiving in log the following:

Mar 23 11:53:06.000 [notice] Now checking whether ORPort 1.2.3.4:443 and DirPort 1.2.3.4:9030 are reachable... (this may take up to 20 minutes -- look for log messages indicating success)
Mar 23 11:53:07.000 [notice] Self-testing indicates your DirPort is reachable from the outside. Excellent.
Mar 23 12:13:06.000 [warn] Your server (1.2.3.4:443) has not managed to confirm that its ORPort is reachable. Please check your firewalls, ports, address, /etc/hosts file, etc.
Mar 23 12:33:06.000 [warn] Your server (1.2.3.4:443) has not managed to confirm that its ORPort is reachable. Please check your firewalls, ports, address, /etc/hosts file, etc.

Firewall and the application which redirects traffic to the 4443 port haven't changed.
What may be the cause of that?