Facebook Link Preview Not Loading ('Could Not Connect' or Missing Image)

When you share a link on Facebook and the preview shows no image, an old image, or an error such as “Could Not Connect To Server. Check that the webserver is running, and that there are no firewalls blocking Facebook’s crawlers”, the cause is usually one of four things. This guide covers them in order, from the quickest to check to the most commonly overlooked.

1. Facebook is showing a cached result

Facebook stores the first result it gets for a URL and keeps showing it, even after you fix the page. If a link was ever shared while your site had a temporary problem, the broken preview can stick.

Fix it with the Sharing Debugger:

Open the Facebook Sharing Debugger at https://developers.facebook.com/tools/debug/.

Paste your URL, click Debug, then Scrape Again to force Facebook to re-read the page.

If the thumbnail still does not appear, change the preview image: re-upload it under a new file name and update the post's featured / Open Graph image, so Facebook treats it as brand new.

The most reliable test is to share the link in a real post (you can delete it afterward). The Debugger sometimes reports a transient error even when the live preview already works.

If the preview returns after re-scraping, you are done. If a brand-new URL that was never shared before also fails, continue to the next cause.

2. Your SSL certificate is invalid or incomplete

Facebook fetches your page and your preview image over HTTPS, and it is strict about certificates. If your certificate is expired, self-signed, issued for a different hostname, or missing its intermediate chain, the crawler’s secure connection fails and you again see “Could Not Connect To Server”, even though the page may open fine in your own browser (browsers are more forgiving than Facebook’s crawler).

How to check:

Open your URL in a browser and confirm the padlock shows with no warning, on the exact address you are sharing (including www versus non-www).

Run the address through an external checker such as https://www.ssllabs.com/ssltest/ and look for "expired", "self-signed", or "incomplete chain".

Confirm your preview image (the og:image URL) is served over https with the same valid certificate, not over http or a different domain whose certificate is broken.

If the certificate is expired or incomplete, renew or reissue it. On our cPanel and LiteSpeed stacks, AutoSSL normally renews certificates automatically; if it did not, open a ticket and we will reissue it for you. Once the certificate is valid, re-scrape the link in the Sharing Debugger (Step 1).

3. A security rule is rate-limiting the crawler

Facebook’s crawler (facebookexternalhit and meta-externalagent) sometimes requests many pages at once, and a server security system can mistake this for abuse and start returning 403 responses. That same restriction can also block the legitimate preview fetch.

This part is managed on the server side. If your previews broke suddenly and Step 1 did not help, open a support ticket with the affected URLs and we will check whether the crawler is being rate-limited and adjust it.

4. Your nameserver domain expired (the hidden cause)

This is the least obvious cause, and the one that breaks previews across all of your domains at once. It sounds unlikely, but we have seen it happen to a few of our customers, so it is worth checking even if it seems far-fetched.

If your domains use custom nameservers based on another domain (for example ns1.yourbrand.com and ns2.yourbrand.com), that nameserver domain must stay registered. If it expires, its DNS is taken over by the registrar’s parking service. Every domain that relies on those nameservers then resolves to a parking page, often with an invalid or expired SSL certificate, instead of your real site.

When that happens:

• Facebook, and eventually all visitors, reach the parking host. The secure connection fails, and you see “Could Not Connect To Server” or HTTP 418.
• It often looks intermittent at first, because many networks still have your correct address cached. As those caches expire it gets worse, and it starts affecting real visitors, not just Facebook.

How to check: look up the registration and expiry date of the domain that provides your nameservers (not only your website domain). If it shows expired, or the nameservers now point to a parking service, this is your cause.

How to fix it:

Renew the nameserver domain right away at its registrar. Once the parking is released and DNS caches expire (usually a few hours), your sites and previews recover on their own.

Or move your domains to RemarkableCloud nameservers, so your DNS no longer depends on that domain staying registered. See RemarkableCloud Nameservers. We can host your full DNS for web and email, which is more robust against future expiries.

After DNS propagates, run any still-broken links once through the Sharing Debugger (Step 1) to clear Facebook's old cached result.

Still stuck?

If you have worked through all four causes and previews still fail, open a ticket with the exact URLs you are testing, and we will trace the request end to end from the server side.