Three subdomains and 404 errors?

First subdomain works. The second loads for and is visible for half a second and then goes to 404. The third works but is stapled as unsafe?

What are the subdomains? Checking an issue is so much easier if people know what to check.
Are the three subdomsins.

All of those subdomains are working fine as far as I can tell. They show website content. Could you try to clear your browser cache and then try again?