i just downloaded Thunderbird from Mozilla because it's the only program I can use to access my hosting email addresses in a easy way, but when I try to add my iCloud account, I get an error.
Here's how I'm trying to configure it (sorry for the Spanish).
Best Answer
These settings work for me, see also https://support.apple.com/HT202304.
Incoming
Outgoing
Username for both should just be your actual username "karlo_lopez", not your whole email address.
VERY IMPORTANT NOTE:
If your Apple ID is protected with two-factor authentication, then you need to setup an app-specific password within your Apple ID account. Enter that password instead of your normal iCloud password when setting up the email address into Thunderbird.