Guide · 2026-05-16
Markdown exportAPI and automation error messages
Use returned API error codes to decide whether to retry, correct invoice data, sign in again, or contact support.
Who this is for
Use this article when a customer sees an error from an integration, automation, or batch workflow and needs to know what action to take.
Common messages
| Message or code | What it means | What to do |
|---|---|---|
| AUTHENTICATION_REQUIRED | The request did not include a usable login or bearer token. | Sign in again or add the missing API token. |
| INVALID_API_KEY | The API key is wrong, expired, revoked, or not valid for this account or endpoint. | Create or copy the correct key. |
| RATE_LIMITED | Too many requests were sent in a short period. | Wait for the retry window, then continue more slowly. |
| PAYLOAD_TOO_LARGE | The uploaded file is over the size limit. | Compress the PDF or split the work into smaller invoices. |
| INVALID_UPLOAD | The uploaded file could not be read as a valid invoice input. | Check that the file is not empty, corrupted, password-protected, or the wrong format. |
| VALIDATION_FAILED | The invoice data has blocking issues. | Review the returned fields and fix the invoice data before retrying. |
| OUTPUT_PROFILE_REQUIRED | The requested output format needs a clearer compliance profile. | Choose the intended profile, such as XRechnung, EN 16931, ZUGFeRD, or Factur-X. |
| OUTPUT_PROFILE_CONFLICT | The chosen format and profile contradict each other. | Pick one matching output target and retry. |
Retry guidance
Retry temporary errors such as timeouts, unavailable services, and some upload failures.
Do not blindly retry validation, authentication, rate-limit, file-size, or profile errors. Those need a correction first.
Related articles
Integrate invoice conversion by API: get access, upload with an idempotency key, poll the task, download the result, and handle validation.
Convert invoices by email: how the channel worksConvert invoice PDFs by email: enable the Enterprise channel, verify senders, choose a format, send attachments, and review the reply.
ERP integration checklist for e-invoicing rollout teamsA practical checklist for ERP e-invoicing projects, covering data mapping, format selection, validation, exception handling, and go-live controls.