Connect Unit4 with eConnect: ERPx via the Autopilot, ERP CR via SFTP, and Financials via HTTPS.
In 2026, Unit4 offers three variants, each with its own integration method. Which one applies depends on your Unit4 product.
You connect Unit4 ERPx via the Autopilot. Purchase invoices are automatically imported and posted. Configuration is set up during implementation with eConnect.
Autopilot configuration runs through a step-by-step wizard in the eConnect platform:
Note: Process all documents through the old route first before switching over. The customer does not configure the connection themselves; this is done during implementation.
When posting via Unit4 ERPx, the message [U4OK.JSON]: System.Int32 overflow may occur. Cause: the invoice number is numerically so large that it exceeds the limit of a 32-bit integer (maximum 2,147,483,647). In that part of the Unit4 processing, the system cannot handle the number. This is a limitation in Unit4 itself, not in the eConnect connection or our integration code.
In practice, you see this with organizations that use very high ranges for outgoing invoice numbers (for example values well above 2 billion).
What can you do? The solution must come from Unit4. Changing the invoice number in the source XML via eConnect is not a viable workaround without risk to your administration and numbering. Unit4 is aware and is working on a structural fix. Until then: escalate to your Unit4 administrator or partner and, if needed, use the XML download from the eConnect platform (Inbox) to support the case.
Unit4 ERP CR (including ERP7) and Unit4 Financials by Coda connect via SFTP and HTTPS respectively. These enterprise integrations require a contract and are configured by Unit4 or a Unit4 partner in collaboration with eConnect.
The standard integration method for Unit4 ERP CR and ERP7 is SFTP (Secure File Transfer Protocol). For more information on how an SFTP connection is set up technically, see the article SFTP integration.
In the past, an invoice could be posted successfully in Unit4 ERPx while the PDF attachment did not come through. The cause was a connection break on the Unit4 side where the PDF was dropped. Since May 2026, these cases are automatically retried, confirmed by Platform & Integrations. In most situations, you should no longer see this problem.
If you still encounter a case where an invoice is posted but the PDF attachment is missing, that is a residual case. Follow the diagnosis path below to determine whether the document was actually lost or whether an idempotent match is involved.
Tip: you can always download the invoice itself from the eConnect platform (Inbox, three dots on the document). If needed, forward the document manually to your Unit4 administrator.
Unit4 ERPx cannot process purchase invoices without a due date (DueDate). When an invoice arrives without this field, eConnect sets the DueDate to the invoice date plus 30 days by default. This prevents the posting from failing on a formally missing field while the actual payment term is usually 30 days in practice.
This compensation is configured per customer as a PrivateObject in the PSB. If you want a different default term, contact support; this is not a self-service setting.
This diagnosis path applies to complaints such as "the invoice shows Booked in eConnect, but I don't see it in ERPx" or "the invoice never seems to have arrived; the Document Journal shows nothing". Background: the Autopilot ↔ Unit4 ERPx route is idempotent (match on invoice number plus customer plus supplier). On a match, eConnect does not call ERPx again and only uploads a missing PDF, while the platform still shows Booked. An empty Document Journal for the second submission usually does not mean the invoice was lost, but that the idempotent check was triggered. See also Autopilot — idempotent posting.
The interpretation of status labels differs per connection type. Determine whether this involves Autopilot (Unit4 ERPx), another PSB route, a direct SOAP API, or an SFTP connection. See the status table in Autopilot — Posting statuses for the meaning per connection type.
Note at least one of these two IDs for the document:
documentId (from the PSB), orconsignmentId (from the platform).Either one is sufficient to look up the document in all internal systems.
Open the document in the internal Management API by documentId or consignmentId and review the Events timeline. This shows per step which action was performed on the document: receipt, validation, submission to ERPx, retries, idempotent match, and PDF upload. For SFTP connections, this is the only place where delivery status is visible, because the software package does not return status feedback via SFTP.
Do you see in the Events timeline that eConnect recognized the invoice as existing (same invoice number, customer, and supplier) and only performed a PDF upload? Then this is expected behavior. The invoice was already in ERPx from a previous submission. Communicate this back to the customer; escalation is not needed.
Only when the Events timeline does not provide a complete picture, escalate to the technical team. Include at minimum:
documentId or consignmentId,partyId,When processing invoices via the ABWInvoice transformation (used in Agresso/Unit4 integrations), the error message [API400]: Initializing failed. Unhandled error occurred. may occur. The cause is that the transformation was built based on the original test documents. Deviating document variants (such as free text invoices) contain fields that are missing from the mapping, causing the transformation to fail.
A change request is in progress to extend the transformation for multiple document types. If you encounter this error message, contact support.
For Unit4 integrations with foreign currency (e.g. USD with exchange rate), currency configuration is the customer's responsibility in the Unit4 environment. eConnect processes what the ERP supplies. Support questions about foreign currency should be referred to the customer ERP configuration.
Error messages that start with the prefix U4 come from Unit4 ERPx. The solution is almost always on the Unit4 side. You can download the XML file yourself from the eConnect platform (Inbox, three dots on the document) and forward it to your Unit4 administrator.
VAT mapping: difference between incoming and outgoing
For incoming invoices (Autopilot), eConnect handles the VAT mapping. You configure the scheme via Platform > Autopilot > Connection > Posting scheme > MANAGE SCHEMES > VAT. For outgoing invoices, eConnect does not handle VAT mapping: Unit4 must supply the correct UNCL5305 codes in the invoice XML.
This is a generic error message that can have multiple causes: a timeout at Unit4, an invoice with more than 200 lines, invoice lines with an amount of € 0, or duplicate VAT codes in the posting scheme. Resubmit the invoice via Inbox. If the error persists, post the invoice manually in ERPx and check the VAT scheme for duplicates.
The combination of supplier and invoice number already exists in Unit4. Check whether the invoice was submitted earlier (for example via another route) and whether the IDR recognized the invoice number correctly. If the invoice is actually a duplicate, you don't need to do anything. If it is a different document with the same number, check the recognition in the eConnect platform.
The invoice XML contains a VAT code that is not in the Autopilot posting scheme. This happens mainly with invoices that arrive by email with a deviating or incorrect VAT code. Add the missing mapping via Platform > Autopilot > Connection > Posting scheme > MANAGE SCHEMES > VAT, or ask the supplier to send the invoice via Peppol (which uses standard VAT codes).
The creditor in Unit4 ERPx has no payment terms configured. eConnect does not supply a due date to Unit4 itself. Set the payment terms on the supplier card in Unit4 ERPx.
The Dummy Crediteur in Unit4 is not active. Activate the Dummy Crediteur in Unit4 ERPx and resubmit the invoices.
The invoice total is € 0.00. An invoice without an amount cannot be posted in Unit4.
The posting cycle in Unit4 ERPx is not configured correctly or is not active for the relevant period. Check and activate the correct posting period in Unit4.
The payment reference on the invoice is longer than 27 characters, which Unit4 does not accept. As a temporary workaround, you can submit the invoice as a PDF instead of via the automatic connection. Structurally, the supplier must shorten the payment reference.
The machine-to-machine (M2M) user that eConnect uses to log in to Unit4 has insufficient rights or has been deactivated. Have the Unit4 administrator check and restore the rights of the M2M eConnect user.
The invoice was posted to the Dummy Crediteur, but an earlier document with the same invoice number is already there. Process the existing invoice on the Dummy Crediteur first, then resubmit the new invoice.
The routing configuration in Unit4 ERPx is missing a node for the specified workflow. This is a Unit4-side issue. Download the XML from the eConnect platform and forward it to your Unit4 administrator to adjust the routing.
The attached PDF contains an invalid "data" prefix in the Base64 data (for example dataJVBERi0x... instead of JVBERi0x...). For invoices that arrive via the IDR, this is corrected automatically. For invoices that arrive directly via Peppol, this problem may still occur. The source sender must correct the XML.
You connect Unit4 ERPx via the Autopilot for automatically receiving purchase invoices. Unit4 ERP CR and ERP7 use SFTP, and Unit4 Financials by Coda connects via HTTPS. Both latter variants require a contract and are configured by Unit4 or a Unit4 partner.
For Unit4 ERPx, configuration is set up during implementation with eConnect, not by the customer themselves. For Unit4 ERP CR and Financials by Coda, configuration is performed by Unit4 or a Unit4 partner in collaboration with eConnect.
::e-accordion-item{value="item-3" header="What should I do about the "Int32 overflow" error with large invoice numbers?"} This is a limitation in Unit4 itself when the invoice number is larger than 2,147,483,647. The solution must come from Unit4. Escalate to your Unit4 administrator or partner and, if needed, use the XML download from the eConnect platform to support the case. ::
Want to connect Unit4? Contact Unit4 or your Unit4 partner, or eConnect sales for an intake call.
Start the connection