"Failed to connect instance"

Dear Sir/Madam,

I am constantly getting the above error, it drives me nuts. I thought it had been caused by certain DNS (domain name system) anomalies (I used Cisco's Umbrella DNS service, and my ISP's one), changing that to google DNS I have still been getting this "Failed to connect instance" error. It is very frustrating, I cannot even finish my first Labyrinth because of this. What exactly is this? Is it a client or server side issue? It happens roughly after 2-3 instance changes. Using a new instance (by CTRL+click) often solves this (but I cannot do that in Lab).

I am located in Hungary in an IPv6 environment, NAT64-ed by my ISP towards IPv4, trying to connect to Frankfurt/Amsterdam/Moscow servers, changing servers do not help the issue, it started ~2 days ago.

Any help would be appreciated!

Best Regards,
xxxyyyzzzhhh

These are the logs I have found so far:

025/03/05 09:37:50 1338424609 88a910a0 [DEBUG Client 5492] Got Instance Details from login server
2025/03/05 09:37:50 1338424609 d5c98b06 [INFO Client 5492] [SHADER] Delay: OFF
2025/03/05 09:37:50 1338424609 ca3a699b [INFO Client 5492] Connecting to instance server at 94.242.197.91:6112
2025/03/05 09:37:55 1338428828 19dc40 [DEBUG Client 5492] [InGameAudioManager] TalkingPetAudioEvent 'LevelUp' triggered
2025/03/05 09:38:12 1338445640 ca3a50da [DEBUG Client 5492] Connect time to instance server was 0ms
2025/03/05 09:38:12 1338445640 aeceac73 [INFO Client 5492] Abnormal disconnect: Failed to connect to instance
2025/03/05 09:38:12 1338446109 e0343728 [DEBUG Client 5492] [SCENE] Height Map Texture: 800 x 800
2025/03/05 09:38:51 1338484718 890d9d74 [INFO Client 5492] Async connecting to fra01.login.pathofexile.com:20481
2025/03/05 09:38:51 1338484750 890d9cff [INFO Client 5492] Connected to fra01.login.pathofexile.com in 0ms.
2025/03/05 09:38:53 1338486906 88a910a0 [DEBUG Client 5492] Got Instance Details from login server
2025/03/05 09:38:53 1338487015 d5c98b06 [INFO Client 5492] [SHADER] Delay: OFF
2025/03/05 09:38:53 1338487015 ca3a699b [INFO Client 5492] Connecting to instance server at 188.42.174.50:6112
2025/03/05 09:38:53 1338487078 ca3a50da [DEBUG Client 5492] Connect time to instance server was 31ms
2025/03/05 09:38:53 1338487187 1186a040 [DEBUG Client 5492] Client-Safe Instance ID = 2545570793
2025/03/05 09:38:53 1338487187 1186a062 [DEBUG Client 5492] Generating level 33 area "1_3_town" with seed 1

Yes, I'm aware that a "to" is missing (Failed to connect TO instance)

Captured the whole thing with Wireshark with this filter:
(tcp.dstport == 6112) && ((tcp.flags.syn == 1) || (tcp.flags.fin == 1))

Even in the same geolocation (based on IP addresses) my session gets a timeout after 4 retransmissions. Other IP addresses previously from the same ISP and geolocation (GSL Networks' addresses on London servers) function without any issues. Does it mean that some DoS protection filters my session, or a DDoS attack consumes all server resources? I'm gonna tweak some TCP settings to see if that's helping or not (e.g changing from default 4 retransmissions), but I think, on my side, this is all I can do now. :(

Checking with a VPN now... from a data center in Paris, IP: 79.127.215.213, to server IPs: 188.42.44.58 (Luxembourg?), 138.199.27.138 and so on, will update this thread if that's helping or not..