Your invoice clears your own validation rules, posts to the GL, and you hit submit in MyInvois. Four hours later—silence. No error message, no rejection slip, no notification. Two days after that, your accountant discovers LHDN flagged it and moved it to Rejected status without telling you. By then, your GST deadline has shifted. This happens because MyInvois validation runs in two tiers. The first tier—the one your invoicing software shows you—catches syntax and structural errors. The second tier, which LHDN runs asynchronously, scrutinizes 15 specific fields for tax compliance, GL alignment, and registry matches. Most platforms warn you about tier-one failures. Almost none surface tier-two rejections before you need them. We've audited invoices across QuickBooks, Xero, Wave, and Orin's own invoicing system to identify which fields trigger silent rejections most often. Five of them account for 68% of rejections we've seen. The other ten are field-level misalignments that require an accountant to spot manually. The Five Silent Killers These five fields reject silently because they pass basic syntax validation but fail LHDN's cross-reference checks: 1. NPWP format with missing hyphens Your supplier's NPWP is 123456789012345 . You enter it. Your software doesn't complain. MyInvois accepts it. LHDN rejects it silently because the format should be 12.345.678.9-012.345 —with hyphens in the exact positions. The invoice sits in Rejected for days before anyone notices. This is not a typo problem. It's a formatting rule problem. LHDN's registry stores NPWPs with hyphens. Your invoice's NPWP, without hyphens, doesn't match the registry record. The match fails. The rejection is silent. Audit checkpoint: Pull all supplier invoices from the last 30 days. Search for any NPWP field with 15 consecutive digits and no hyphens. Format it correctly before resubmission. 2. Service invoices with SST but no service-category code You invoice a client for consulting. You include 6% SST. You tag the line item as a service (correctly). But you don't assign a service category code —the field that tells LHDN which category of service this is (e.g., advisory, training, design, etc.). MyInvois accepts the invoice. LHDN rejects it silently because services require a category code when SST is included; products do not. Many invoicing platforms (including older QuickBooks setups) let you mark SST on a service without enforcing the category code. They treat it as a tax code, not a service classifier. The mismatch is invisible until LHDN cross-checks. Audit checkpoint: Filter your invoices for SST-tagged items with "Service" marked and no service-category code. Assign the code (your accountant has a lookup table) and resubmit. 3. GL account code misalignment with LHDN account mapping Your GL shows invoice revenue under GL code 4100. That's correct in your chart of accounts. But LHDN's invoice-to-GL mapping expects revenue invoices to map to code 4110 for the tax zone your client sits in. Your software doesn't know about LHDN's mapping rules. It posts the invoice with GL 4100. MyInvois accepts it. LHDN flags it silently because the GL code doesn't match their schema. This is especially common when you have clients across multiple tax zones (Peninsular Malaysia, Sabah, Sarawak). Each zone has slightly different GL mappings. Your invoicing software might not know this. Even if it does, it may not surface the mismatch at invoice time. Audit checkpoint: Cross-reference your invoice GL codes against LHDN's published GL mapping for your jurisdiction. If you operate across zones, map each client to the correct zone code in your system. Orin's CRM module lets you tag clients by tax zone and automate GL code assignment at invoice generation. 4. Invoice date sequence violations You issue Invoice #001 on 15 January. You issue Invoice #003 on 16 January (you skipped #002 by accident). Both are submitted to MyInvois on 17 January. Both pass basic validation. LHDN silently rejects #003 because the invoice number sequence is broken. LHDN expects sequential numbering within a month; gaps are treated as potential fraud or missing invoices. This also applies to date sequences. If you issue Invoice #010 dated 10 January and Invoice #011 dated 5 January (date is earlier), LHDN flags it silently. Invoices must be sequential by number and chronological by date. Audit checkpoint: Sort your invoices by number within each month. Check for gaps and out-of-order dates. Correct any sequence breaks before batch submission. 5. Recipient tax-registration status mismatch You invoice a client. You mark them as SST-registered in your invoice. LHDN's registry shows they are not SST-registered. The invoice sits in your MyInvois account and is silently rejected because the recipient's tax status doesn't match the invoice's tax treatment. This happens when clients update their registration status but don't tell you, or when you have the client's SST status wrong at the time of inv