Right after connecting a custom domain, it's completely normal to briefly see a security warning in your browser (something like "can't provide a secure connection" or a certificate mismatch error). This isn't a sign anything is actually broken.
Why this happens
Connecting a domain is really two separate steps: your DNS record pointing correctly, and an SSL certificate being issued for that exact domain. DNS usually resolves first (often within minutes), the certificate can lag behind it by anywhere from a few minutes to a few hours.
What to check
- Confirm the DNS record your project's Custom Domain settings asked for was entered exactly as shown, a typo in the record's name or value is the most common real mistake.
- Use an independent DNS checker like dnschecker.org to confirm the record is actually visible from multiple locations, not just to you.
- If the DNS record checks out correctly everywhere, simply wait, this resolves itself once certificate issuance finishes, nothing further is needed from you.
Tip: Still failing after several hours with a confirmed-correct DNS record? Reach out with the domain name, that's no longer a normal propagation delay and worth us looking at directly.