Nine times in ten it is one of two things: the DNS record has not spread across the internet yet, or the record does not exactly match what Rennt asked for. Work the list in order.

1. Wait first#

DNS changes take anywhere from minutes to 24–48 hours to propagate. If you added the record less than an hour ago, get a coffee, then press Check / Connect on the domain under Your domains again. Repeated clicking does not speed it up.

2. Re-check the record, character by character#

At your registrar, compare against what the Custom domain tab asked for:

• Right type? CNAME and A are different things.
• Host exactly right? A common trap: entering "rentals.yourbusiness.com" as the host when the registrar wanted just "rentals" — many registrars append your domain automatically, quietly creating rentals.yourbusiness.com.yourbusiness.com.
• Value pasted whole, with no trailing spaces?

3. Hunt for conflicting old records#

If the domain used to point at an old website, delete the stale A or CNAME records on the same host — DNS with two contradictory lines fails unpredictably.

4. Proxy toggles off#

Using Cloudflare? Set the record to "DNS only" (gray cloud), not proxied (orange). The proxy hides the record Rennt needs to see.

Still stuck?#

Email support@rennt.app with your domain name and a screenshot of your DNS records page — that is everything needed to spot the mismatch, usually in one reply.