HTTP Errors - plex.tv Not Resolving

Plex Media Server
1

Server Version#: 1.23.2.4584
OS: Ubuntu 20.04.2 LTS (GNU/Linux 5.4.0-73-generic x86_64)

I started getting DNS errors from by Ubuntu Plex Server this AM, which is preventing playback, avatars, etc. from completing successfully.

Example of errors in the Plex Log:

May 26, 2021 13:39:13.279 [0x7f09ffd16b38] Warning — [MediaProviderManager] HTTP error requesting GET https://plex.tv/media/providers?X-Plex-Token=xxxxxxxxxxxxxxxxxxxx (6, Couldn't resolve host name) (Could not resolve host: plex.tv)
May 26, 2021 13:39:13.279 [0x7f09ffd16b38] Error — [MediaProviderManager] Error parsing content.
May 26, 2021 13:39:13.279 [0x7f09ffd16b38] Error — [MediaProviderManager] Error parsing XML: Error parsing file.
May 26, 2021 13:39:13.279 [0x7f09ffd16b38] Debug — [MediaProviderManager] HTTP requesting GET https://plex.tv/media/providers?X-Plex-Token=xxxxxxxxxxxxxxxxxxxx
May 26, 2021 13:39:18.286 [0x7f09ffd16b38] Error — [MediaProviderManager] Error issuing curl_easy_perform(handle): 6
May 26, 2021 13:39:18.286 [0x7f09ffd16b38] Warning — [MediaProviderManager] HTTP error requesting GET https://plex.tv/media/providers?X-Plex-Token=xxxxxxxxxxxxxxxxxxxx (6, Couldn't resolve host name) (Could not resolve host: plex.tv)

I verified these URL’s complete successfully manually via wget and curl from the terminal, but when I run nslookup there appears to be a problem as it’s responding with SERVFAIL:

> plex.tv
Server:         127.0.0.53
Address:        127.0.0.53#53

Non-authoritative answer:
Name:   plex.tv
Address: 99.81.153.144
Name:   plex.tv
Address: 99.81.164.127
Name:   plex.tv
Address: 108.128.10.254
** server can't find plex.tv: SERVFAIL

I set nslookup to resolve directly against Cloudflare (1.1.1.1):

> plex.tv
Server:         1.1.1.1
Address:        1.1.1.1#53

Non-authoritative answer:
Name:   plex.tv
Address: 108.128.10.254
Name:   plex.tv
Address: 99.81.153.144
Name:   plex.tv
Address: 99.81.164.127
** server can't find plex.tv: SERVFAIL

as well as Google (8.8.8.8), with the same result:

> plex.tv
Server:         8.8.8.8
Address:        8.8.8.8#53

Non-authoritative answer:
Name:   plex.tv
Address: 99.81.164.127
Name:   plex.tv
Address: 99.81.153.144
Name:   plex.tv
Address: 108.128.10.254
** server can't find plex.tv: SERVFAIL

Is Plex having an issue with DNS resolution??? That’s my only guess at this point as other domains are resolving fine through nslookup on the same machine.

2

Same problem. It looks like they pulled 4584 running on a synology here

3 
[chuck@lizum /tmp.512]$ nslookup plex.tv
Server:		127.0.0.53
Address:	127.0.0.53#53

Non-authoritative answer:
Name:	plex.tv
Address: 99.81.164.127
Name:	plex.tv
Address: 108.128.10.254
Name:	plex.tv
Address: 99.81.153.144

[chuck@lizum /tmp.513]$

Not seeing the DNS issues on Linux itself.
If you have main Linux DNS resolution problems, check your resolver.

If this is docker PMS and the issue is confined to WITHIN the container only then I need to hear about it please

4

It doesn’t seem to be an issue internally with the resolver as other domains resolve without issue from the same machine:

> google.com
Server:		127.0.0.53
Address:	127.0.0.53#53

Non-authoritative answer:
Name:	google.com
Address: 64.233.177.113
Name:	google.com
Address: 64.233.177.102
Name:	google.com
Address: 64.233.177.139
Name:	google.com
Address: 64.233.177.138
Name:	google.com
Address: 64.233.177.100
Name:	google.com
Address: 64.233.177.101
Name:	google.com
Address: 2607:f8b0:4002:c08::65
Name:	google.com
Address: 2607:f8b0:4002:c08::8a
Name:	google.com
Address: 2607:f8b0:4002:c08::71
Name:	google.com
Address: 2607:f8b0:4002:c08::8b
>

> forums.plex.tv
Server:		127.0.0.53
Address:	127.0.0.53#53

Non-authoritative answer:
forums.plex.tv	canonical name = plex.hosted-by-discourse.com.
Name:	plex.hosted-by-discourse.com
Address: 216.218.159.24
Name:	plex.hosted-by-discourse.com
Address: 2001:470:1:9f1::24
>

This is not Docker PMS. The plex dpkg is installed on Ubuntu directly.

5

This same error started happened exactly after I upgraded my Synology version to 1.23.2.4584. 95% sure it is tied to that update on my end somehow. The update isn’t available to download from plex.tv anymore so assume it was pulled.

1 Like
6

Further debugging leads me to believe this issue is IPv6 related.

> set q=AAAA
> plex.tv
Server:         192.168.7.1
Address:        192.168.7.1#53

** server can't find plex.tv: SERVFAIL
>

> set q=A
> plex.tv
Server:         192.168.7.1
Address:        192.168.7.1#53

Non-authoritative answer:
Name:   plex.tv
Address: 99.81.164.127
Name:   plex.tv
Address: 108.128.10.254
Name:   plex.tv
Address: 99.81.153.144
>

The only DNS error I’m able to recreate consistently is the missing AAAA record on plex.tv

Did something change in the most recent release/package where curl would be trying to resolve the ipv6/AAAA record (-6 maybe?) which would result in curl reporting resolution issues?

7

thanks. Guess it’s time for me to go :clubs: something :smiling_imp:

FYI: Plex doesn’t publish any IPv6 addresses. It’s something Operations is working on completing. (I’ve been urging them as best I can)

8

Ok happy to help if I can. I’m getting lots of colourful errors “server is unclaimed”, remote access is obviously not connecting and it’s still saying an update is available but we seemed to be orphaned on 4584 at this point and an older version is up for download from your site.

I bet downgrading off this version will be a quick fix?

9
  1. server won’t claim if it cant resolve plex.tv to authenticate & record the ownership.
  2. uninstall what you have and installing an older is an easy attempt to temp fix.

Regarding the DNS,

  1. Operations needs IPv6 support (fully). Too many folks have recently lost their IPv4.
  2. PMS 1.23.x is using a new toolchain. In it, the resolver works differently.
  3. My hypothesis is:
    a. Host is dual stack
    b. WAN is IPv4 only or IPv6 only
    c. Resolver chooses the wrong IP stack and can’t find its way out of that wet paper bag.

I can’t verify this because

  1. I have dual stack WAN
  2. and dual stack LAN.

Changing that up will break the world.

I’ve tried VMs without success.

Any thoughts?

10

Thanks for the follow-up! So on this Ubuntu host, I’ve disabled IPv6 entirely in order to try and trouble shoot this issue:

enusbaum@xxxxx:/var/log$ cat /proc/sys/net/ipv6/conf/all/disable_ipv6
1

enusbaum@xxxxx:/var/log$ ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
2: eno1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 94:c6:91:a6:78:44 brd ff:ff:ff:ff:ff:ff
    inet 192.168.7.91/24 brd 192.168.7.255 scope global dynamic eno1
       valid_lft 10545sec preferred_lft 10545sec
3: wlp0s20f3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 04:d3:b0:88:28:59 brd ff:ff:ff:ff:ff:ff

Not sure how else to nudge the resolver towards ipv4.

11

nudging the resolver – /etc/resolv.conf

12

Potential Fix for the in the toolchain?

curl_easy_setopt(easy_handle, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4);

13

Can confirm my /etc/resolv.conf only has one line, which is my Gateway IP for resolution.

I can run curl locally through the command line on the URL’s and it’s working just fine.

Plex:

[MediaProviderManager] HTTP error requesting GET https://plex.tv/media/providers?X-Plex-Token=xxxxxxxxxxxxxxxxxxxx (6, Couldn't resolve host name) (Could not resolve host: plex.tv)

Terminal (same machine):

enusbaum@xxxxx:~$ curl https://plex.tv/media/providers?X-Plex-Token=xxxxxxxxxxxxxxxxxxxx
<?xml version="1.0" encoding="UTF-8"?>
<errors>
  <error code="1001" message="User could not be authenticated" status="401"/>
</errors>
14

I downgraded to 1.23.1.4571 and the problem persists. The key errors are:

  1. can’t enable remote access
  2. under general settings I get “server is unclaimed and unsecure” but not possible to claim it.
  3. “Conversion failed. A required codec could not be found or failed to install.” when try to watch anything from local library

pretty sure all related to the plex.tv not resolving

15

Be VERY careful please in stating “plex.tv not resolving”.

  1. On the host, resolution is ok
  2. Within the confines of the new compiler’s runtime library (gibc equivalent) – it is failing interfacing to the host.

We’re trying to find out exactly where this fault is occurring.

WHEN we catch it in the act, we will be able to fix it.
We just need access to a host long enough to reproduce it happening.

1 Like
16

Thanks.

Would you expect this to present as a hard or intermittent?

17

All the cases I’ve seen present as a hard failure.

curl https://plex.tv/blah-blah fails to resolve plex.tv

(this is how we verify it in docker containers)

18

@enusbaum

Can you create a temporary docker PMS container which:

  1. Demonstrates the failure – you should since your host does too.
  2. In the container, Execute the option to set resolution
  3. Next issue curl against Plex.tv (using your PlexOnlineToken)
19

I haven’t really worked with Docker, but let me see what I can put together this afternoon and get it back to you.

Thanks!!

20

If you need a quicky script to automate it, I’ll give you mine.

It’s not hard. ( I can do it so it CAN’T be hard … LOL )