Issue symptoms
My agents see the below error when they try to sign in to my host-mapped account: yoursubdomain.zendesk.com refused to connect.
Resolution steps
The error yoursubdomain.zendesk.com refused to connect comes from privacy settings blocking third-party cookies. Host-mapped Zendesk accounts have the sign-in page URL support.yoursubdomain.com and the underlying Zendesk page related to the sign-in cookie support.yoursubdomain.com. Some web browsers, ad-blockers, and privacy-related extensions block cookies because of this URL mismatch.
To solve this issue, ensure the browser allows third-party cookies from Zendesk. Find the instructions to allow third-party cookies in Chrome in this article from Google Chrome Help: Clear, enable, and manage cookies in Chrome.
If your browser has ad-blockers, turn them off to see if this allows you to sign in. Some ad-blockers have their list of exceptions. If that is your case, add yoursubdomain.zendesk.com to the allow list.
For more information, see the article: I am having trouble logging in to Zendesk.