Why do my https requests hang for several minutes?

I make https request from a react native app. Sometimes the requests hang for about 2 minutes (no reject, no resolve). Here are some symptoms:

  • It looks like it happens only on some network (4G works, wifi doesn’t)
  • It comes and goes (can work 100 times, then stop working)
  • looks like https fails when http succeeds
  • The same requests work perfectly in Chrome (same device, same network)
  • I use react native with expo
  • tried fetch & axios

What else can I check?