Railway doesn't use IP addresses for custom domains - you need to set up a CNAME record instead. In your service's Settings tab under Public Networking, click your custom domain to see the CNAME value Railway provides (something like abc123.up.railway.app). Update your DNS to create a CNAME record pointing to that value, not an A record with an IP. If you're using a root domain (like example.com without www), your DNS provider needs to support CNAME flattening - Cloudflare and Namecheap do, but GoDaddy and Hostinger don't. Once your CNAME is correctly configured, Railway will automatically provision an SSL certificate, which usually takes under an hour but can take up to 72 hours. If you're using Cloudflare, make sure your SSL/TLS mode is set to "Full" (not "Full Strict" or "Flexible") to avoid certificate errors.