Your anchor does not perfectly match the brief: an extra space, a comma, an accent, a hyphen... can be the cause, so you must check your anchor carefully.​

Your link does not perfectly match the brief: often an omission or addition of the "/" at the end of your URL.​

Our validation system has difficulty in correctly identifying the anchor and/or the URL, especially if you use a solution such as Cloudflare, which prevents us from finding the URL. ​

In this case, it is imperative that you contact us so that we can validate it manually.​

Last possible case, it could simply be a bug, it can happen, where our system does not manage to identify anchor and url.