@Paris_Meijer - this error indicates that there’s an issue with the connection b/w your computer and that Asana servers. There isn’t currently an Asana outage (check here for future reference), so there may be some issue with your specific account/domain.
Your best bet is to follow the below steps to create a ticket. In your initial message, include as much relevant info as you can (browser/desktop/mobile, browser/app version, machine type, are you on a company network, etc.) to expedite your request.