When I access laravel forge (https://forge.laravel.com), there exist warning like this :
Forge IP Addresses: We are upgrading our servers! If you use IP whitelisting, please add our new addresses: xxx.xxx.xxx.xxx and xxx.xxx.xxx.xxx.
Seems It will add new address. But i'm still confused to add it
Whether it is added in digital ocean via ssh?
How can I solve this problem?
Depending on what yuou have configured security wise, you'll likely need to add new firewall rules for the ip addresses. As it says, if you've whitelisted forge servers anywhere you'll have to do the same for these.
You may have a whitelist defined through your webserver as well.