Testnet doesn't synchronize

Hi everyone. I am trying to synchronize my pc with the testnet, but it always remains at zero. I’ve tried using Sandbox and also install a node natively, but the result is still the same. The node is successfully started and I also tried to do the fast catchup, but it doesn’t work. Can anyone help me? thank you so much

Can you verify that from inside the sandbox container that you have access to the network?

  1. Break the fast catchup attempt with ^c
  2. Hop into the container sandbox enter algod
  3. Run ping google.com

When I run the sandbox, even by the time it hits fast-catchup I’ve imported some blocks.

This is the output, but i didn’t understand very well what you mean. I’m sorry but I’m a beginner with Algorand and also with Ubuntu

Are you behind a proxy?
Can you run curl http://example.com?