Docker container stopped working after a few days - it can't connect to foundryvtt.com

[lig76]

Hi,

I've successfully setup Docker container with FoundryVTT on Qnap NAS server. I managed to run it on 443 with UPnP port forwarding and it was working like a charm. However since last weekend the container stopped see central foundryvtt.com server and thus it can't perform any updates, not download modules. I didn't touch the configuration during that time.
I have even decided to turn SSL off, but it didn't change anything.

In the logs I see:

FoundryVTT | 2024-04-16 12:57:49 | [info] Software license verification succeeded
FoundryVTT | 2024-04-16 12:57:49 | [info] Requesting UPnP port forwarding to destination port 443
FoundryVTT | 2024-04-16 12:57:49 | [info] Server started and listening on port 443
FoundryVTT | 2024-04-16 12:57:54 | [warn] Could not reach IP discovery service
FoundryVTT | 2024-04-16 13:06:42 | [info] Created client session 553ce3cd5868cbf5d8657f07
FoundryVTT | 2024-04-16 13:06:48 | [info] Administrator authentication successful for session 553ce3cd5868cbf5d8657f07
FoundryVTT | 2024-04-16 13:06:54 | [warn] The Foundry Virtual Tabletop website could not be reached to check for core software updates

Issuing command nslookup ended up with:

/home/foundry # nslookup foundryvtt.com
Server:         127.0.0.11
Address:        127.0.0.11:53

Non-authoritative answer:

Non-authoritative answer:
Name:   foundryvtt.com
Address: 18.237.161.213

/home/foundry # 

Besides this container I had second test container with similar configuration. It was also working fine (on port 30000) but also stopped contact foundryvtt.com

Now, the funny part. I have created fresh container today. And this one is working seamlessly . No issues with updating / downloading modules.
Logs:

FoundryVTT | 2024-04-16 13:12:48 | [info] Software license verification succeeded
FoundryVTT | 2024-04-16 13:12:48 | [info] Server started and listening on port 30000

This one has exactly the same version as those old ones.

The nslookup command produces this result:

/home/foundry # nslookup foundryvtt.com
Server:         127.0.0.11
Address:        127.0.0.11:53

Non-authoritative answer:

Non-authoritative answer:
Name:   foundryvtt.com
Address: 18.237.161.213

/home/foundry # 

I'm out of ideas, what could go wrong.

Could you please help ?
Thank you.

[lig76]

Nothing helped withing container setup.
I have used option "Recreate Container".

Finally, it works w/o loosing data.