warningDEPEPPOL_BIS
DE-R-028:Invalid email format. The seller contact email (BT-43) must contain exactly one @ sign with at least two characters on e
Invalid email format. The seller contact email (BT-43) must contain exactly one @ sign with at least two characters on each side, and no dots at start or end.
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.
Common Causes
- Seller email address format invalid
- BT-43 must contain exactly one @ with valid structure
- cbc:ElectronicMail missing @ or has invalid format
- Email has whitespace around @ or invalid characters
- Dot at start/end or adjacent to @ in email address
Frequently Asked Questions
Invalid email format. The seller contact email (BT-43) must contain exactly one @ sign with at least two characters on each side, and no dots at start or end.
Invalid email format. The seller contact email (BT-43) must contain exactly one @ sign with at least two characters on each side, and no dots at start or end. You can also use Invoice Navigator's automatic Fixer tool to correct this instantly.
DE-R-028 is a warning that may not always cause rejection, but it indicates a potential compliance issue that should be addressed.
Many instances of DE-R-028 can be automatically corrected using Invoice Navigator's Fixer tool. Upload your invoice and the tool will identify and fix common issues.
See Also
Last updated: 16 January 2026
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