Slack Links Not Opening? Here's What to Check

Written by Proovd — proovd.in.

Last verified September 19, 2026 against Slack’s help article “Share links and set preview preferences,” workspace “Manage link previews,” and api.slack.com/robots.

One page for the whole cluster: links not opening, links not working, and link preview / unfurl not showing.

Slack links not opening

People search “Slack links not opening” when a message contains a URL that will not launch. Open Graph is irrelevant here. Work through:

1. Does the text include a scheme? Slack’s own help says previews may not expand if http:// (or https://) is missing. Bare example.com is also a common reason a click does nothing useful.
2. Try the same URL in a browser. If it fails there, the site is down, geo-blocked, or needs a VPN — not Slack.
3. Desktop app vs browser Slack. Workspace links sometimes open in the browser instead of the app (or the reverse) because the OS protocol handler for slack:// is wrong. Reinstalling the desktop app re-registers that handler. Slack’s help for connection issues is the right place if the app itself will not load.
4. Corporate browsers. Extensions, pop-up blockers, and “don’t open external links” policies intercept clicks. Test in a private window with extensions off.

If the page loads when you paste the URL into Chrome but Slack’s click does nothing, it is still an app/OS problem. Skip the rest of this article’s website section.

Slack link preview not working (unfurls)

When someone shares a link, Slack can show a text preview under the message. Slack calls this unfurling. Official reasons a preview does not display (Slack help):

• The page has no preview data (no usable Open Graph, Twitter Card, or oEmbed tags).
• The page or file is private / login-gated.
• The same link was already shared in that conversation within the past hour — Slack will not expand it again.
• The message contains more than five links.
• Audio/video from a host Slack has not allowlisted (their list, not yours).

Your preferences

Profile photo → Preferences → Messages & media → under Inline media & links, “Show text previews of linked websites” and “Show images and files from linked websites.” If those are off, you will not see unfurls. Other people in the channel still might.

Workspace-blocked domains

Owners and admins can block previews for a website (hover the preview → close → “Also block previews from this website”). Admins review that list under Workspace settings → Attachments → Blocked previews. There is no current Slack setting named “Message Prefill” for this; older articles that mention it are stale.

What Slackbot actually fetches

From Slack’s robot documentation:

• User-agent Slackbot-LinkExpanding 1.0 (+https://api.slack.com/robots) reads as little of the page as it can (HTTP Range) for oEmbed and Twitter Card / Open Graph tags.
• Slack-ImgProxy then fetches referenced images.
• Responses are cached globally for about 30 minutes.
• Slack does not honor robots.txt. Blocking Slackbot in robots.txt will not stop unfurls. A WAF challenge or 403 will.

Tags must be in the bytes Slackbot requested — typically the start of the HTML. Client-rendered meta tags never appear in that response.

Website fixes

<meta property="og:title" content="Your Title" />
<meta property="og:description" content="Your description" />
<meta property="og:image" content="https://yoursite.com/image.jpg" />

Use absolute HTTPS image URLs that return 200 without cookies. Then delete the old Slack message (or wait ~30 minutes) and re-post. Slack documents a URL debugging tool for admins; Proovd is a third-party preview of the same tags across Slack and other apps, not Slack’s internal debugger.

Quick checklist

Frequently asked questions