API problem types / Public tools
HTTP 404 · Not Found
Link not valid
https://corplyst.com/problems/tax-check-link-invalid
What it means
The Form 5472 reminder link has expired, was already used, or its email address was removed.
What to do
Run the free Form 5472 check again to get a new email with fresh links.
Example response
Sent with Content-Type: application/problem+json. The detail field describes this specific occurrence.
{
"type": "https://corplyst.com/problems/tax-check-link-invalid",
"title": "Link not valid",
"status": 404,
"detail": "…"
}