Hi, @davestewart. Our DNS instructions for all third-party DNS service (and DNS service besides Netlify DNS) are found here:
For your domain, the DNS records should look like this:
davestewart.co.uk. 21600 IN A 104.198.14.52
www.davestewart.co.uk. 21600 IN CNAME davestewart.netlify.app.
However, instead they look like this:
davestewart.co.uk. 21600 IN A 76.76.21.21
www.davestewart.co.uk. 21600 IN A 104.198.14.52
So, step #1, you will need to correct the DNS records above.
We are not done though. There are two additional steps required to fix this.
Step #2, make the www
subdomain the “primary custom domain” here:
https://app.netlify.com/sites/davestewart/settings/domain#custom-domains
Right now, the apex domain (davestewart.co.uk
) is primary. However, this is using the A record and the A record is a single system in California. If you make this domain primary then all site traffic for anyone in the world will go only to California. Obviously, this is not what you want.
Making the www
subdomain primary will use the CNAME record. and that CNAME using geographical routing to return IP addresses of the closest ADN nodes. You can see the geographical routing of IP address if you query the site subdomain from different locations around the world, for example - by using this DNS checking tool:
https://dnschecker.org/#A/davestewart.netlify.app
This shows the CNAME returning many different IP addresses around the world (not just 104.198.14.52
). Now, let’s check your current A record:
https://dnschecker.org/#A/www.davestewart.co.uk
It is sending all global traffic to one IP address in California. The wrong DNS is the root cause.
Again, making the www
primary (and fixing the DNS record is step one) will fix this.
Step #3, is to delete the inactive Netlify DNS zone here:
Click the “Delete DNS zone” button on that page. There is a support guide to explain why here.
Do not skip step #3. If you skip this step, the SSL certificate will stop working when it expires because renewals will fail.
To summarize the steps for the solution, they are:
- Correct the existing DNS records.
- Make the
www
subdomain the primary custom domain for the site at Netlify.
- Delete the inactive Netlify DNS zone.
If there are any questions about this, please let us know.