Hi.
Since a few days, we often see errors on CI where builds are failing because hackage does not respond in a timely manner:
Tue, 10 Mar 2026 10:59:20 GMT Downloading timestamp
Tue, 10 Mar 2026 10:59:20 GMT Downloading snapshot
Tue, 10 Mar 2026 10:59:50 GMT SomeRemoteError (HttpExceptionRequest Request {
Tue, 10 Mar 2026 10:59:50 GMT host = "hackage.haskell.org"
Tue, 10 Mar 2026 10:59:50 GMT port = 443
Tue, 10 Mar 2026 10:59:50 GMT secure = True
Tue, 10 Mar 2026 10:59:50 GMT requestHeaders = [("Accept-Encoding",""),("User-Agent","Haskell pantry package")]
Tue, 10 Mar 2026 10:59:50 GMT path = "/snapshot.json"
Tue, 10 Mar 2026 10:59:50 GMT queryString = ""
Tue, 10 Mar 2026 10:59:50 GMT method = "GET"
Tue, 10 Mar 2026 10:59:50 GMT proxy = Nothing
Tue, 10 Mar 2026 10:59:50 GMT rawBody = False
Tue, 10 Mar 2026 10:59:50 GMT redirectCount = 10
Tue, 10 Mar 2026 10:59:50 GMT responseTimeout = ResponseTimeoutDefault
Tue, 10 Mar 2026 10:59:50 GMT requestVersion = HTTP/1.1
Tue, 10 Mar 2026 10:59:50 GMT proxySecureMode = ProxySecureWithConnect
Tue, 10 Mar 2026 10:59:50 GMT }
Tue, 10 Mar 2026 10:59:50 GMT ResponseTimeout)
Tue, 10 Mar 2026 10:59:50 GMT
Tue, 10 Mar 2026 10:59:50 GMT Error: [S-5170]
Tue, 10 Mar 2026 10:59:50 GMT While trying to unpack HUnit-1.6.2.0, Stack encountered an error.
As you can see we are using stack. Also note the request failed after 30 seconds, which is exactly the ResponseTimeoutDefault. (this was run on Github provided runners see Add test for unpacking · avdv/stack@ebb41d5 · GitHub)
I tried to reproduce with curl, and one time I indeed saw some weird hangup:
curl -v -m 30 https://hackage.haskell.org/package/logict-0.7.0.3.tar.gz -o /dev/null
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
0 0 0 0 0 0 0 0 0* Host hackage.haskell.org:443 was resolved.
* IPv6: (none)
* IPv4: 151.101.0.68, 151.101.64.68, 151.101.128.68, 151.101.192.68
* Trying 151.101.0.68:443...
* ALPN: curl offers h2,http/1.1
} [5 bytes data]
* TLSv1.3 (OUT), TLS handshake, Client hello (1):
...
* Server certificate:
* subject: CN=*.haskell.org
* start date: Feb 9 16:18:57 2026 GMT
* expire date: Mar 13 16:18:56 2027 GMT
* issuer: C=BE; O=GlobalSign nv-sa; CN=GlobalSign Atlas R3 DV TLS CA 2026 Q1
* Certificate level 0: Public key type RSA (2048/112 Bits/secBits), signed using sha256WithRSAEncryption
* Certificate level 1: Public key type RSA (2048/112 Bits/secBits), signed using sha256WithRSAEncryption
* Certificate level 2: Public key type RSA (2048/112 Bits/secBits), signed using sha256WithRSAEncryption
* subjectAltName: "hackage.haskell.org" matches cert's "*.haskell.org"
* SSL certificate verified via OpenSSL.
* Established connection to hackage.haskell.org (151.101.0.68 port 443) from 192.168.1.117 port 53384
* using HTTP/1.x
} [5 bytes data]
> GET /package/logict-0.7.0.3.tar.gz HTTP/1.1
> Host: hackage.haskell.org
> User-Agent: curl/8.18.0
> Accept: */*
>
* Request completely sent off
0 0 0 0 0 0 0 0 00:07 0{ [5 bytes data]
< HTTP/1.1 301 Moved Permanently
< Connection: keep-alive
< Content-Length: 0
< Server: nginx/1.24.0 (Ubuntu)
< Content-Type: text/plain
< Location: /package/logict-0.7.0.3/logict-0.7.0.3.tar.gz
< Accept-Ranges: bytes
< Via: 1.1 varnish, 1.1 varnish
< Date: Tue, 10 Mar 2026 08:20:38 GMT
< X-Served-By: cache-dfw-kdfw8210050-DFW, cache-fra-etou8220058-FRA
< X-Cache: MISS, MISS
< X-Cache-Hits: 0, 0
< X-Timer: S1773130831.082936,VS0,VE7547
<
0 0 0 0 0 0 0 0 00:07 0
* Connection #0 to host hackage.haskell.org:443 left intact
Note that it took 7 seconds after the request was sent off until the headers arrived.
According to APDEX on https://hackage.haskell.org/ status page – updown.io I should be happy, yet CI is failing all over again 
Anyone experiencing the same issue?
