How do I fix DE-R-027?

Invalid phone number format. The seller contact telephone number (BT-42) must contain at least 3 digits to be valid. You can also use Invoice Navigator's compliance engine to correct this automatically in your pipeline.

Is DE-R-027 a critical error?

DE-R-027 is a warning that may not always cause rejection, but indicates a compliance issue.

Can DE-R-027 be automatically fixed?

Many instances of DE-R-027 can be automatically corrected using Invoice Navigator's compliance engine. The fix is applied in your pipeline with full audit evidence.

warningDEUPEPPOL_BIS

`DE-R-027`:Invalid phone number format. The seller contact telephone number (BT-42) must contain at least 3 digits to be valid.

Invalid phone number format. The seller contact telephone number (BT-42) must contain at least 3 digits to be valid.

Severity

Warning

Rule set

PEPPOL_BIS

Country

DEU

Fix type

CONFIRM

Confidence

80%

Engine Classification

Requires user confirmation before application

What is DE-R-027?

DE-R-027 is a warning validation rule defined in the PEPPOL_BIS specification (DEU national rules). It validates the Telephone element under Party > Contact in the UBL invoice XML.

This is a soft validation failure. The invoice may pass initial transmission, but non-compliant values in this field can cause problems during tax audits, buyer-side processing, or downstream VAT reconciliation.

Target path: //cac:AccountingSupplierParty/cac:Party/cac:Contact/cbc:Telephone

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Why This Error Matters

Invoice will be rejected by German XRechnung validators. German e-invoicing has specific format requirements for payment details, contact information, and attachments.

DE-R-027 is a soft failure. The invoice may pass initial validation, but the non-compliant field can cause issues at the receiving end — tax authorities may flag it during audits, buyer ERP systems may fail to process it, or VAT reconciliation may produce mismatches. Fixing warnings before they accumulate prevents larger compliance gaps.

Validator Behavior

·Generates validation warning
·Rejected by PEPPOL Access Points
·Rejected by XRechnung endpoints
·Error returned: DE-R-027
·Specification: PEPPOL_BIS

XML Example

Generic example based on the rule's target XPath. Your actual XML structure may differ.

Before

<!-- Incorrect value -->
<cbc:Telephone>INVALID</cbc:Telephone>

After

<!-- Corrected value -->
<cbc:Telephone>VALID_VALUE</cbc:Telephone>

Technical Reference

XPath//cac:AccountingSupplierParty/cac:Party/cac:Contact/cbc:Telephone

SpecPEPPOL_BIS

Operationset_default

StrategyEnsure seller contact telephone is present for XRechnung

Common Causes

·Seller telephone number format invalid
·BT-42 must contain at least 3 digits
·cbc:Telephone too short or contains only text
·Contact phone number not valid format
·Telephone field contains non-numeric or too few characters

Seeing this in production? The API handles DE-R-027 automatically. See the fix response →

Last updated: 27 February 2026

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Handle DE-R-027 Automatically in Your Pipeline

The compliance engine auto-remediates this error with controlled safety policies and evidence pack generation.

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DE-R-027:Invalid phone number format. The seller contact telephone number (BT-42) must contain at least 3 digits to be valid.