I’m experiencing weired behavior in my local network and/or internet connection.
It seems that some requests fail for unknown reasons. I’m experiencing this with different devices in my network, but the issues are gone if I connect to another network.

While this is not truly a ‘programming’ question, it significantly affects my ability to work/program properly.. So I don’t see any other options than asking for help here. I really hope you can help me.

The symptoms are the following:

• GraphQl requests are failing sometimes to certain servers, e.g.

curl 'https://graphql.datocms.com/' 
    -H 'Authorization: 12345' 
    -H 'Content-Type: application/json' 
    -H 'Accept: application/json' 
    --data-binary '{ "query": "query { allPosts { title } }" }'

curl: (35) Recv failure: Connection reset by peer

If I try this multiple times, about 50% of the requests fail. If I do the query from a node application, it sometimes fails with this:

➜ node query.js
node:internal/deps/undici/undici:12502
      Error.captureStackTrace(err, this);
            ^

TypeError: fetch failed
    at node:internal/deps/undici/undici:12502:13
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
  [cause]: Error: read ECONNRESET
      at TLSWrap.onStreamRead (node:internal/stream_base_commons:218:20) {
    errno: -54,
    code: 'ECONNRESET',
    syscall: 'read'
  }
}

For other servers it seems to always work, e.g:

curl --location 'https://swapi-graphql.netlify.app/.netlify/functions/index' 
--header 'Content-Type: application/json' 
--data '{"query":"{rn  allFilms {rn    films {rn      titlern    }rn  }rn}","variables":{}}'

{"data":{"allFilms":{"films":[{"title":"A New Hope"},{"title":"The Empire Strikes Back"},{"title":"Return of the Jedi"},{"title":"The Phantom Menace"},{"title":"Attack of the Clones"},{"title":"Revenge of the Sith"}]}}}

• Other tools that download something, sometimes fail
  
  If I try it again, it would work at some point

• Some requests on websites sometimes fail
  
  Again, this only happens sometimes.

What I’ve tried so far:

• Restart Router, restart Laptop, reset Router to factory settings. No effect.
• Try with different devices (2 Macbooks, Windows Laptop) in the same network. Same behavior.
• Try with cable instead of wifi. No effect.
• Connect to shared hotspot from my phone via LTE. Issue gone!
• Look for suspicious settings in the router interface, didn’t find anything, but also wasn’t sure what to look for.
• Speed-test, e.g. on https://www.speedtest.net/de. Looks all good.
• ping google.com. This looks like this:

➜  exp ping google.com
PING google.com (172.217.16.174): 56 data bytes
64 bytes from 172.217.16.174: icmp_seq=0 ttl=116 time=11.254 ms
64 bytes from 172.217.16.174: icmp_seq=1 ttl=116 time=11.364 ms
64 bytes from 172.217.16.174: icmp_seq=2 ttl=116 time=12.189 ms

After about ~50 calls, sometimes I get a Request timeout for icmp_seq 75

I think the issues just started today at some point, during the last weeks everything was working as expected, as far as I can tell. So it might just be an issues with my provider? (o2 in Germany)

I really really hope you can help me or point me into a direction on how to approach this issue. Thank you so much!