Transmission says port CLOSED, but it's not

Hello,

can I ask you for help with this, please?

I'm just an amateur, but everything worked until maybe a month ago (the last time I wanted to use transmission).

I wanted to use it today and it's still not working, so I'm asking here.

I set up docker, transmission container and everything was fine for ~1 year.

And now when I want to use it, it says it cannot access tracker - wanted to download ubuntu for my friend (50MB/s vs 2MB/s from official).

I didn't reset the router with the port forward, I didn't replace the router. It just stopped working.

Screenshot:

Transmission -

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Portchecker -

Thanks for any help.

Up

No, IPV6 is disabled and IPV4 is on DHCP. Like it always was.

Up

Hello, I hope you mean this?

I set up this thing by some guide before.
Screenshot:

Up

It says that I'm using Linuxserver.io version:- 3.00-r0-ls57 Build-date:- 2020-06-06T19:59:49+02:00

So it should be older than 3.13 or not?

Quote from sandbox404

the newest version use alpine 3.13 has known issue, change the image version to transmission:3.00-r0-ls73 to solve this temporary, it is the last version use alpine 3.12

I did it all again, pulled ls73 (there was some bug showing I'm running ls57 but it was using the 79), did a complete restart...

And still the same:

----------------

Success: I can see your service on 89.xxxxx on port (51413)

Your ISP is not blocking port 51413

Does anyone know what to do? Or where to ask?