A TTN submission error means your invoice did not clear El Fatoora—so it is not legally issued under the e-invoicing framework, even if you already emailed a PDF to the customer. Finance teams see these errors under deadline pressure; a structured triage list beats guessing.
This guide covers rejection patterns Tunisian PMEs report during TEIF submission and clearance. Exact error codes evolve with TTN releases—always cross-check the latest TTN operator message and your accountant's interpretation.
Certificate and signature failures
TEIF invoices require a valid digital certificate from an accredited provider. Expired certificates, wrong certificate bound to the company tax ID, or signing on the wrong workstation are the top causes of cryptographic rejection.
- Verify certificate expiry date and renewal calendar
- Confirm certificate matches enrolling company, not a personal ID
- Ensure signing service is reachable from the machine submitting
- After renewal, restart integration and rerun test invoice
Buyer and seller master data errors
TTN validates structured identifiers for both parties. Missing buyer tax ID on B2B invoices, malformed address blocks, or special characters in legal names trigger schema validation failures before business rules even run.
VAT line and total mismatches
Line-level VAT rates must sum to header totals within tolerance rules TEIF enforces. Mixed-rate invoices, rounding differences between Excel and software, and manual discount lines are frequent culprits.
- Reconcile line math
Check each line: quantity × unit price − discount + VAT = line total.
- Compare header totals
Sum of lines must match invoice total fields in TEIF export.
- Validate rate codes
Use VAT categories your sector actually declares—do not copy rates from unrelated templates.
- Resubmit test
Use TTN test channel if available before production resubmit.
Duplicate numbering and timing
Invoice number sequences must stay unique and chronological per series rules your accountant defines. Restoring backups, importing old numbering, or two users issuing the same next number causes duplicate rejection.
Integration and connectivity errors
Timeouts, HTTP 5xx from TTN, or SFTP upload failures are operational—not fiscal—but still block clearance. Log timestamps, retry with backoff, and avoid duplicate submissions that could confuse reconciliation.
When to escalate
- Same error after master data and math fixes—escalate to software vendor with TEIF XML sample
- Certificate valid but signature still fails—contact certificate provider
- Buyer insists data is correct but TTN rejects—accountant verifies buyer enrollment
- Platform-wide TTN outage—pause submissions, document downtime for audit
Hesabi aims to surface TTN errors in context and preserve audit trails. Regardless of tool, maintain a one-page internal runbook linking to this triage order so substitutes can act when primary finance is unavailable.
Credit notes and cancellations
Errors discovered after clearance require structured credit notes linked to original TTN references—not informal email corrections. Software should preserve linkage for auditor traceability; your accountant defines legal wording.
Train finance to capture full TTN error payload (code, message, timestamp) in a shared log. Patterns across weeks reveal systematic master data issues versus one-off buyer mistakes.
During TTN platform maintenance windows, queue drafts but do not assume clearance succeeded because HTTP returned 200—verify reference and QR presence before customer delivery.
Sector-specific gotchas
Service companies with mixed exempt and taxable lines need explicit product catalog discipline—do not let sales free-text descriptions that software cannot map to VAT codes.
Retail with cash register integration may delay TTN submission until end of day batch; ensure batch totals still tie to individual cleared documents your accountant expects.
Export-oriented firms must confirm buyer foreign identifiers are captured when TEIF requires them; domestic-only templates fail silently until clearance.
Build an internal FAQ from your own error log after 90 days—generic web advice rarely matches your catalog and customer mix as well as your documented fixes.
Pair this guide with choosing-invoicing-software-tn when errors trace to bad master data at import—software cannot fix tax IDs you never collected from customers.
Assign one finance owner as TTN error DRI; rotating blame between IT, sales, and cabinet paralyzes resolution when clearance volume spikes.
Pre-submission checklist (printable)
- Certificate valid and bound to company
- Buyer tax ID present for B2B
- VAT math reconciled line to header
- Invoice number unique in series
- Line descriptions match catalog VAT codes
- Signing service online
- Previous rejection notes reviewed if reissue
Run the checklist until it becomes muscle memory—most senior finance staff still skip step two when rushing month-end batches.
Hesabi users should attach TTN error screenshots to the invoice record so auditors and accountants see resolution history without email archaeology.
Review TEIF schema updates when TTN publishes release notes—silent schema changes cause sudden mass rejections across unchanged invoices.
Save TTN operator phone support hours in the same runbook—vendor outages happen on peak declaration days.
Customer already paid—invoice rejected?
Do not treat PDF as final; fix and re-clear, then send official reference. Payment reconciliation may need adjustment.
Can we skip TTN for small amounts?
Only if law and scope explicitly allow—confirm with accountant, not sales judgment.
Error message in French only?
Map keywords (certificat, TVA, identifiant) to categories above; accountant translates edge cases.
How long to retry?
After fixing root cause immediately; avoid hammering API during outages.
Hesabi outside Tunisia?
No. Tunisia-only product.
