Hi Sílvia Formigo,
try to reset network connections: Open PowerShell or CMD and run as administrator, copy and paste the following commands by pressing enter at the end of each command line:
netsh winsock reset
netsh int ip reset
netsh advfirewall reset
ipconfig /flushdns
Restart the computer at the end of all commands.
If it doesn't solve it, come back here and specify the model of your ethernet network adapter, you can find it from Device Manager>network adapters.