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Short answer: If a link shows a connection error instead of loading, the request is being blocked before it reaches ShortPen. Test the same link on mobile data with WiFi off. If it opens there, the block is on the original network: a firewall, a DNS filter, or security software. Connecting your own domain removes the dependency on the shared shr.pn domain permanently.

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What the error looks like

The browser shows one of these instead of your destination page:
  • This site can't be reached
  • shr.pn refused to connect
  • ERR_CONNECTION_REFUSED
  • ERR_NAME_NOT_RESOLVED
  • ERR_CONNECTION_TIMED_OUT
  • DNS_PROBE_FINISHED_NXDOMAIN
  • An antivirus or security page naming the domain as unsafe or suspicious
All of these mean the browser could not reach the server at all. It never got as far as loading a page, so this is not a broken link, a wrong destination, or an expired slug.
1

Test on mobile data

Open the link on a phone with WiFi turned off. If it opens, the link works and the block is on the other network.
2

Test the same link from a different network

Try a home connection, a colleague on another network, or a phone hotspot. If it works everywhere except one place, that place is blocking it.
3

Test a second ShortPen link

If every shr.pn link fails on that network but works elsewhere, the whole domain is blocked, not one link.
If the link opens on mobile data, stop troubleshooting the link and read below.
If the link fails on every network and every device, it is not a network block. See Best Practices and Troubleshooting for ShortPen links or contact support.

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Why networks block shared shortener domains

  • shr.pn is a shared domain used by every ShortPen user who has not set a custom domain on the link.
  • Security tools treat shared shorteners cautiously because the final destination is hidden until the redirect resolves.
  • A single abusive link created by any user of any shortener can put the whole domain on a blocklist.
  • This affects every shortener equally, including Bitly, TinyURL, Short.io, and Rebrandly.
The same reputation problem is why shr.pn links can land in spam folders.
See Why use a custom domain with ShortPen?
The block usually sits in one of four places:
  • A corporate firewall
  • A DNS filter (Cisco Umbrella, Zscaler, NextDNS, Pi-hole and similar)
  • Antivirus web protection (Norton, Kaspersky, Bitdefender and similar)
  • The ISP
ShortPen monitors the reputation of shr.pn, applies stricter automated checks and rate limits on the shared domain, and submits it for review with reputation providers when it gets flagged. ShortPen cannot force a third-party network, IT department, or security vendor to unblock a domain. ShortPen cannot see or influence a block that happens inside someone else’s network.

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How to fix it

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If you control the network (or can ask IT)

  • Ask your IT or network administrator to allow shr.pn in the firewall.
  • Ask them to allow it in the DNS filter and any web security tool.
  • Check antivirus and browser extension web protection settings on the affected machine.
  • If a security tool shows a category such as URL shorteners or uncategorized, request the exception for that category, not for the single link.

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If you don’t control the network

Connect your own domain. Your links then run on a domain only you use, with a reputation tied only to your own activity. This is the only fix that works when the block sits on a recipient’s network rather than your own. Follow How to connect a custom domain to ShortPen, then verify the DNS records before you start sharing links on the new domain.
Changing the domain creates a new link and the previous one stops working. Any QR code already printed with the old domain must be re-downloaded and reprinted.
See What happens to a QR code after changing a link?
Custom domains are available on all plans.

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What to send support if you’re still stuck

Include all of the following in your first message:
  • The full short link (domain and slug)
  • The exact error message, copied or screenshotted
  • Whether it works on mobile data with WiFi off
  • The network type (home, office, university, public WiFi) and country
  • Device, operating system, and browser

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FAQ

Clicks that never reach ShortPen are never recorded, so a network block can make traffic look lower than it is. Open Real-time Activity while you test the link to confirm whether a click is registering at all, then compare with link-level metrics.
No. Only the network owner or the security vendor that maintains the blocklist can do that. ShortPen can submit the domain for review with reputation providers, but cannot override a decision made inside a private network.
It can in theory, but reputation follows usage. On a domain only you use, only your own activity affects it.
Blocks are applied per network, per organization, and sometimes per security product. The same link can open in one office and fail in another.