Why is SEMRush reporting a 404 error on our Webflow website that includes our site URL followed by a colon ("/:")? How can we fix this issue?
TL;DR
- Locate and fix any links with href="/:" in your Webflow project, especially in CMS items, nav menus, or custom code.
- Republish your site and re-run the SEMRush crawl to confirm the broken URL is no longer detected.
SEMRush is reporting a 404 error for a URL ending in "/:" because it's detecting a malformed or nonexistent URL structure. This isn't a valid URL path in Webflow, and likely results from crawler misinterpretation, incorrect links, or third-party scripts.
1. Understand Why the "/:" URL Triggers a 404
- Webflow does not support pages or paths ending with "/:" — colons in URLs without a proper structure are invalid and will trigger a 404.
- SEMRush may be picking this up from:
- A faulty internal or external link on your site or site map.
- A JavaScript-based link that’s rendered incorrectly (e.g.,
href="/:"). - Improper link interpolation, such as
href="/:slug"that's not replaced dynamically.
2. Search for the Faulty Link in Your Webflow Project
- Use Webflow Designer’s Navigator and check all pages, nav menus, buttons, and custom code areas for:
- Broken
href="/:" - Links using dynamic fields that may be missing or not binding correctly
- Also review your CMS Collections for empty slug fields or incorrect URL references.
3. Check Custom Code Blocks and Embeds
- Inspect any custom HTML embeds or third-party scripts you’ve added, such as:
- Custom nav menus
- External integrations that inject anchors or links
- Look specifically for any anchor tags like
<a href="/:">or string concatenations that produce it.
4. Review Your Sitemap and Robots.txt
- Go to Project Settings > SEO tab and download your auto-generated sitemap.xml.
- Search for any entries containing
/:— if it's there, fix the source. - If needed, manually exclude this URL by editing the sitemap or blocking it in
robots.txt(but fixing the source is the best solution).
5. Re-Run the SEMRush Crawl After Fixing
- Once the faulty link is removed or corrected:
- Publish your site in Webflow.
- In SEMRush, rescan your site to check that the 404 is no longer present.
Summary
The 404 error for a malformed /: URL is caused by a broken or mistyped link in your Webflow project, likely from a static or dynamic href field. Search for and correct any links with /:, especially in CMS, custom code, or nav elements. Then republish your site and re-crawl with SEMRush to confirm the issue is resolved.