Most Cloudflare problems come down to three things: the SSL mode, the DNS records, or the cache. Start with the problem that matches what you see.
"Too many redirects" (ERR_TOO_MANY_REDIRECTS)
Cloudflare's SSL mode is probably Flexible while your site also redirects to HTTPS. Open Crypto and set SSL to Full or Strict, then click Save Changes. See Cloudflare: SSL/TLS Settings.
Error 521: Web server is down
Cloudflare reached your server but it refused the connection. Check that your hosting service is active in the Client Area and that the website loads when Cloudflare is paused (Pause Cloudflare on Site on the Overview page). If it's still down, open a support ticket.
Error 522: Connection timed out
Cloudflare couldn't reach your server at all. On the DNS page, check that the A record for your domain (and www) points to your hosting server's IP address. You'll find the right IP in cPanel's General Information panel as Shared IP Address, or in your welcome email. See Cloudflare: Manage Your DNS Records.
Error 525: SSL handshake failed
Cloudflare is set to Full or Strict but your server isn't answering over HTTPS. Install a certificate on your hosting (Install a Free SSL Certificate), or switch the SSL mode to Full while you fix it. With Strict, an expired or self-signed certificate also causes error 526.
"Not secure" right after you switched to Cloudflare
Cloudflare issues its free certificate after your domain moves to its nameservers. This usually takes minutes but can take up to 24 hours. Also see Website shows "Not secure" or an SSL certificate error.
Your changes aren't showing
Purge the cache or turn on Development Mode. See Cloudflare: Clear the Cache and Use Development Mode.
Email stopped working after the switch
Your mail records probably weren't copied to Cloudflare, or a mail hostname is proxied. On the DNS page, check your MX and TXT (SPF) records and make sure mail-related records are DNS only (grey cloud). See DNS Records Needed for Liberation Email and Hub for Teams.
An error inside the Cloudflare manager
If the manager shows a message such as "Authentication error", take a screenshot and open a support ticket. It's on our side and we'll fix it.
More help: My website is down: a step-by-step troubleshooting checklist. When you open a ticket, include your domain name and a screenshot of what you see.
