Server Version#: had latest, downgraded to 1.30.2.6563
Player Version#: latest
I have plex for years, everything was fine untill 2 or 3 days ago. Remote access stopped working, didnt change anything, called my internet provider also to check if they changed something - nothing.
Tried everything that come’s on my mind - downgrading, manually specify public port, port forwarding… no help. Really dont know what to do and what causes problem. Remote access shows that is ok and then in few minutes its no longer available.
Like i said - it was working and i dint change anything…
Pls help
Your logs are showing Double NAT.
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Do you have two routers (or ISP modem-router + second router) ?
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Did DSM update ? (They frequently ‘secure’ the firewall during updates)
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As final check, Plex.tv sees your Public IP as a ‘188.252.x.x’ address
When you log into your modem/router and check what it shows as WAN address, do you get the same thing?
r 03, 2023 20:39:00.088 [0x7f27a388fb38] DEBUG - [EventSourceClient/pubsub/139.162.134.185:443] MyPlex: reachability check - current mapping state: 'Mapped - Publishing'.
Mar 03, 2023 20:39:00.088 [0x7f27a388fb38] ERROR - [EventSourceClient/pubsub/139.162.134.185:443] MyPlex: mapping failed due to potential double NAT configuration
Mar 03, 2023 20:39:00.088 [0x7f27a388fb38] DEBUG - [EventSourceClient/pubsub/139.162.134.185:443] MyPlex: mapping state set to 'Mapped - Not Published (Double NAT)'.
The best way to figure out why PMS is complaining
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start with Settings - Server - Remote Access
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Does it still show your Manual Port forwarding configuration as you set it up?
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Log into each device between you and where the Internet comes in.
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One of them must not have a proper port forwarding
problem is that 3 days ago i didnt have manual port forwarding set at all. Remote access was working without that. In my router also dint have any port forwarded. Now its not working with port forward or without. It shows Fully accessible for couple of minutes and then shows not available…Dont know what to check and i’m not familiar with this. Really need help for dummies 
If there’s need for new log i’ll upload another
Totally understand.
Your logs have already shown me what I need to see. I won’t need more at this point.
4 days ago – the world was good.
Now - the world hates you . (happens to me all the time)
It happens to all of us 
We need to walk through what might have changed.
The one thing which can change in an instant - Synology Firewall.
- Is it enabled & active ?
- If it is, and you use it normally, is the rule which allows Plex also active ?
No, firewall is not active on synology
and tnx for those words, it made me laugh a little. big tnx for trying to help
I also noticed strange behavior on Tautulli logs. For some users it shows that they are connecting on my server via same IP address and apparently some of them succeeded to connect yesterday also. Same adress, different users, different towns…
Direct remote access isn’t working but you have or had Plex relay enabled in the settings which lets people stream from your server through Plex without remote access enabled.
If you have double NAT and don’t control both routers and/or don’t have a public IP then remote access will never work in that way and you’ll have to rely on Plex relay instead.
I had plex relay enabled for long time. It was working just fine with same settings. Now its not working with or without relay, and this is first time i saw those strange IP adress in my tautulli logs. If i disable that relay its the same thing, not available…
Instead of doing double NAT can you just bridge the second router to the first using the LAN ports on it’s switch instead of the Internet port? This would get rid of double NAT.
STUPID question.
Do you have a “Mesh” style Wifi, Plex on that WiFi, and then that WiFi connected to the ISP modem/router ?
plex is on synology connected with cable to router directly, not connecting with wifi
If the Syno is connected via wire to the router – Perfect answer.
A lot of people connect their server over WiFi … which isnt good
They further use Mesh-style (something new) which acts just like a 2nd router
The end result : Plex → Mesh wifi/router → Real router → ISP (Double NAT)
Do this ?
- When you log into your ISP’s modem router.
- Find in there somewhere where it shows the WAN IP address.
- Make sure it doesn’t start with
– 100.
– 10.
– anything in the 172.16->172.31 range
If everything worked “Until 3 days ago”. And today is “March 3rd”.
What did the ISP change?
First thing that i did (before asking for help here) - called internet provider. They said that they didnt change anything. Yes, my wan is 100.smtn
Here’s why I ask:
CGNAT has its own reserved IP range between 100.64. 0.0 and 100.127. 255.255 . If you check your phone’s current IP address (if you’re on mobile data and not WiFi) then if you have an address in that range, you’re, most likely, using CGNAT.
Look at that IP again. If the above applies
THEN
If they implemented CGNAT company wide –
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You’ve already got one layer of NAT because they aren’t giving you a Public IP
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Your modem/router is the 2nd layer.
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PMS is properly detecting the Double NAT and unable to support remote access
Recommendation:
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Look and confirm if your WAN IP is in the standard range
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Use http://whatsmyip.org to confirm your real IP.
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Contact the ISP again. - ASK if you are now behind CGNAT.
You’ve got the evidence.
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If so, ASK if you can subscribe to a real PUBLIC IP again. (Most allow it for another $5 / month))
Yep mines been doing it constantly for the last few days, sometime works for an hour, sometimes a few seconds. Worked fine for years before that.
Thank you. Called my ISP again but this time I was rude… Everything is working like it should now…
They removed CGNAT
@peritissima
Glad that is sorted out. It sounded like CGNAT from the instant you told me the IP started with 100.
@javpanda
Repeat the checks for your real IP and what the modem is reporting to you.
