Help! Custom Domain Suddenly Stopped Working on Hydrogen – 404 Error (May 7, 2025)

[blindboxphilipp]

Hi everyone,

I’m reaching out to see if anyone has experienced a similar issue or might have a solution.

Our Hydrogen-built Shopify site was working perfectly with our main domain theblindboxfactory.com, and also with www.theblindboxfactory.com. However, since Wednesday, May 7, both versions of the domain have started returning a 404 error.

What’s strange is that the site still works when we set the primary domain to the default Hydrogen preview link:
https://the-blindbox-factory-496cf34d6e65094d0ab4.o2.myshopify.dev/

We haven’t made any changes on our end. This was only brought to our attention when my employee reported the issue. We’ve reached out to Shopify customer support, tried adding additional DNS settings (A records and CNAME), but nothing has fixed it so far.  But I am confident that the problem is on the domain setup mainly because it runs on https://the-blindbox-factory-496cf34d6e65094d0ab4.o2.myshopify.dev/ if i set it to primary. While it won't work on theblindboxfactory.com.

I’m open to trying any recommendations or troubleshooting steps you can share. If you’ve encountered this before or have any insights, I’d truly appreciate the help!

Thanks in advance,
Chris

[Stevepro099]

Hi Chris,

It definitely sounds like a domain connection issue, not a problem with your Hydrogen build. If the site works on your Oxygen preview link but not on your custom domain, here are the main things to check:

1. Domain status in Shopify admin
   Go to Settings > Domains and confirm that both theblindboxfactory.com and www.theblindboxfactory.com are listed and marked as “Connected.” If either shows “Not connected” or “SSL pending,” that’s likely the issue.

2. DNS settings
   Double-check your domain’s DNS settings:

• The A record for @ should point to 23.227.38.65

• The CNAME record for www should point to shops.myshopify.com
  Also make sure there are no extra A or AAAA records that might conflict with Shopify’s setup.

1. Oxygen setup
   If you're deploying to Oxygen, make sure your custom domain is properly added and verified in the Oxygen dashboard for your Hydrogen app. Even if DNS is correct, the domain won’t work unless it’s linked to your storefront there.

2. SSL certificate
   Sometimes an issue with the SSL certificate can cause a 404. In your Shopify admin, check that the SSL certificate for your domain is active. If it’s stuck on “Pending,” that can block access.

3. Primary domain setting
   Set either the www or non-www version as your primary domain and redirect all traffic to it. This helps avoid conflicts between versions.

4. DNS propagation
   If you’ve made changes recently, it might just be a matter of time. DNS changes can take up to 48 hours to fully propagate.

If you’ve confirmed all of the above and it’s still returning a 404, try removing and re-adding the domain in both Shopify and the Hydrogen/Oxygen project to reset the connection.