Hello,

I've searched Google and the forums for this problem. While there are others with a similar issue, mine is a little odd.

First, here is a month of logs:

Code:
2019-08-18 07:36:07.853863|INFO    |ServerLibPriv |   |TeamSpeak 3 Server 3.9.1 (2019-07-02 13:17:23)
2019-08-18 07:36:07.853945|INFO    |ServerLibPriv |   |SystemInformation: Linux 4.15.0-52-generic #56-Ubuntu SMP Tue Jun 4 22:49:08 UTC 2019 x86_64 Binary: 64bit
2019-08-18 07:36:07.853968|INFO    |ServerLibPriv |   |Using hardware aes
2019-08-18 07:36:07.854115|INFO    |DatabaseQuery |   |dbPlugin name:    SQLite3 plugin, Version 3, (c)TeamSpeak Systems GmbH
2019-08-18 07:36:07.854143|INFO    |DatabaseQuery |   |dbPlugin version: 3.11.1
2019-08-18 07:36:07.854239|INFO    |DatabaseQuery |   |checking database integrity (may take a while)
2019-08-18 07:36:08.044709|INFO    |SQL           |   |database updated successfully to revision: 32
2019-08-18 07:36:08.045391|INFO    |DatabaseQuery |   |database busy, waiting for finishing index tasks, may take some time!
2019-08-18 07:36:48.108056|INFO    |Accounting    |   |Licensing Information
2019-08-18 07:36:48.108113|INFO    |Accounting    |   |type              : Non-Profit License
2019-08-18 07:36:48.108157|INFO    |Accounting    |   |starting date     : Mon May 13 00:00:00 2019
2019-08-18 07:36:48.108210|INFO    |Accounting    |   |ending date       : Wed Nov 13 00:00:00 2019
2019-08-18 07:36:48.108251|INFO    |Accounting    |   |max virtualservers: 10
2019-08-18 07:36:48.108288|INFO    |Accounting    |   |max slots         : 512
2019-08-18 07:36:48.141810|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-18 07:36:48.580562|INFO    |              |   |Puzzle precompute time: 453
2019-08-18 07:36:48.580823|INFO    |FileManager   |   |listening on 0.0.0.0:30033
2019-08-18 07:36:48.624339|INFO    |Query         |   |listening for query on 0.0.0.0:10011
2019-08-18 07:36:48.624480|INFO    |Query         |   |listening for query ssh on 0.0.0.0:10022
2019-08-18 07:36:48.624559|INFO    |CIDRManager   |   |updated query_ip_whitelist ips: 127.0.0.1/32, ::1/128,
2019-08-19 07:36:48.297166|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-20 07:36:48.349982|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-21 07:36:48.414763|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-22 07:36:48.513870|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-23 07:36:48.619805|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-24 07:36:48.722937|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-25 07:36:48.818401|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-26 07:36:48.930666|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-27 07:36:49.026239|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-28 07:36:49.124153|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-29 07:36:49.221283|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-30 07:36:49.326039|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-08-31 07:36:49.422871|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-09-01 00:00:48.178261|INFO    |VirtualSvrMgr |   |executing monthly interval
2019-09-01 00:00:48.178909|INFO    |VirtualSvrMgr |   |reset virtualserver traffic statistics
2019-09-01 07:36:49.527806|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-09-02 07:36:49.628393|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-09-03 07:36:49.761873|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-09-04 07:36:49.868373|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-09-05 07:36:49.962651|INFO    |              |   |myTeamSpeak identifier revocation list was downloaded successfully - all related features are activated
2019-09-05 10:37:53.174543|ERROR   |Accounting    |   |Error contacting server https://accounting2.teamspeak.com: RESOLVE_ERROR: Host not found (non-authoritative), try again later
2019-09-05 10:37:58.181066|ERROR   |Accounting    |   |Error contacting server https://backupaccounting2.teamspeak.com: RESOLVE_ERROR: Host not found (non-authoritative), try again later
2019-09-05 14:37:53.167755|ERROR   |Accounting    |   |Error contacting server https://accounting2.teamspeak.com: RESOLVE_ERROR: Host not found (non-authoritative), try again later
2019-09-05 14:37:55.062264|ERROR   |Accounting    |   |Error contacting server https://backupaccounting2.teamspeak.com: RESOLVE_ERROR: Host not found (authoritative)
As you can see everything works fine until accounting tries to reach the server.
Accounting seems not be able to resolve the hostname accounting2.teamspeak.com.
But the server can reach myTeamSpeak, it downloads the revocation list successfully.

I'm running teamspeak in a official docker container v3.9.1 from here https://hub.docker.com/_/teamspeak
My host is running Ubuntu 18.04.3 LTS with Docker Engine Version 19.03.2

If I exec into the container with
Code:
docker exec -ti wfx-teamspeak sh
and execute
Code:
nslookup accounting2.teamspeak.com
I get this response:

Code:
/var/ts3server # nslookup accounting2.teamspeak.com
nslookup: can't resolve '(null)': Name does not resolve

Name:      accounting2.teamspeak.com
Address 1: 104.20.75.196
Address 2: 104.20.74.196
That '(null)' is coming from the missing second parameter in nslookup. If I use Google's DNS:

Code:
/var/ts3server # nslookup accounting2.teamspeak.com 8.8.8.8
Server:    8.8.8.8
Address 1: 8.8.8.8 dns.google

Name:      accounting2.teamspeak.com
Address 1: 104.20.74.196
Address 2: 104.20.75.196
Ping works, too:

Code:
/var/ts3server # ping accounting2.teamspeak.com
PING accounting2.teamspeak.com (104.20.75.196): 56 data bytes
64 bytes from 104.20.75.196: seq=0 ttl=59 time=11.544 ms
64 bytes from 104.20.75.196: seq=1 ttl=59 time=11.719 ms
I absolutely don't know why Teamspeak can't resolve only the accounting hostname.

I wish accounting would try to refresh the license more often or to be able to do it manually. This way I could debug this better.

When will be the next time when accounting tries to reach the server? Is it doing it only once and thats it? I fear it won't retry it again until my license expires if I ditch docker now and let it run normally.