C2B00013C2B / B2C resultM-Pesa error C2B00013: Invalid Amount (Reject)
This is a C2B / B2C result code — it applies to customer-to-business validation or business-to-customer disbursement flows.
What causes it
During C2B validation the paid amount fails your rules (for example the wrong amount for the invoice).
How to fix it
Return this reject code when the amount is invalid, or relax the amount check if partial payments are allowed.
How paylod handles this
paylod records and decodes every C2B and B2C result, and lets you test the flow without hosting your own validation and confirmation callbacks — so you spend less time on Daraja plumbing and edge-case result codes.
See the paylod M-Pesa API