
Common causes include invalid matter numbers, closed matters, wrong client entities, missing purchase orders, or work outside authorized engagement dates.

Timekeeper and Rate Errors
Invoices may fail because a timekeeper is unapproved, a rate is not authorized, the classification is wrong, or the effective date does not match client records.
Narrative Problems
Vague descriptions, block billing, prohibited terminology, missing purpose, excessive confidential detail, duplicate narratives, and administrative work can all create review problems.
Billing-Code Problems
Missing task or activity codes, invalid codes, the wrong code set, and narrative-code mismatches are common eBilling issues.
Staffing Problems
Client guidelines may restrict partner participation, multiple attendees, research staffing, clerical work, or new timekeepers without approval.
Budget and Scope Problems
Invoices may be reduced when a budget or phase cap is exceeded, work falls outside scope, preapproval is missing, or expenses exceed a limit.
Billing Increment Problems
Clients may specify billing increments, rounding, minimum units, or rules for short tasks. The firm's default should not override the client's written rule.
eBilling File Errors
Technical errors include missing fields, invalid dates, tax errors, unsupported currency, duplicate invoices, mathematical mismatch, and format problems. LEDES publishes standardized error codes for many of these issues.
Prevent Problems at the Source
Fix the earliest stage that owns the issue: wrong matter at matter selection, vague narrative at lawyer review, wrong code at time entry, rate mismatch in finance master data, and file-format errors in eBilling generation.

Build a Rejection Taxonomy
Record rejection category, client, matter, value affected, correction time, root cause, owner, and preventive action. Avoid one generic reason called 'invoice rejected.'
Measure First-Pass Acceptance
Useful measures include first-pass technical acceptance, rejection rate, resubmission rate, average correction time, client adjustment rate, code error rate, and rate rejection rate.
How MIRA Fits
MIRA works upstream of invoice generation. It helps firms prepare clearer reviewed time entries, suggest task and activity codes, and apply review controls before approved time moves toward finance systems.
Related Resources
Authoritative References
This guide is for educational purposes only. Billing, accounting, client, and professional-conduct requirements vary by firm, engagement, and jurisdiction.
Frequently Asked Questions
Why do legal invoices get rejected?
Common reasons include invalid matter or timekeeper data, rate mismatches, vague narratives, block billing, incorrect codes, staffing-rule violations, and technical eBilling errors.
Can timekeepers prevent invoice rejection?
They can prevent many source-entry problems by selecting the right matter, confirming duration, writing clear narratives, and applying required codes.
Is an eBilling rejection the same as a client reduction?
No. A technical rejection may prevent submission, while a client reduction occurs after the invoice is reviewed.
Can AI prevent every rejection?
No. AI can flag routine issues, but client rules, scope, approvals, and judgment still require human review.

