[zuora/zuora-coding-agent]: 53100320 missing existingAccountNumber means the order request omitted the account number. 53100080 subscription not eligible for renewal means auto-renewal is not enabled on the subscription or the renewal term settings are missing. 53100070 already renewed means the term was already renewed once and cannot renew twice. Zuora REST errors put the detail in the reasons array with code plus message; codes starting with 5 or 6 are resource-specific, codes starting with 9 are auth-related (90000011 is invalid credentials in the request header). Pass processId to Zuora support for troubleshooting.

Context: Zuora Order API renewal calls fail with eight-digit error codes. The codes tell you exactly what is wrong.