[IT COllect] - "already in use" where I have no posted ledgers

Posting to Ledgers, produces a "already in use" where I have no posted ledgers to be found.
https://staging-itc-cpic.itdashboard.gov/v1/services/015000200102/ledgers

Json: {"agencyId":"2021FS056DMEAgency","costItem":"IRS Operations Support (One Year)","year":2021,"amount":0.790924,"type":"DME","costPool":"Internal Labor","ITTower":"End User","fundingSource":"015-45-0919","source":"Internal Funding","ledgerElementStyle":"Funding Sources Only","isRetired":false}

Response: 422
Result: {"@context":"\/contexts\/ConstraintViolationList","@type":"ConstraintViolationList","hydra:title":"Validation Errors Encountered","hydra:description":"Found `1` constraint violations","violations":[{"propertyPath":"agencyId","message":"Property agencyId with value 2021FS056DMEAgency is already in use. The property agencyId must be unique.","code":null}],"hydra:request_id":"0c4864fa-9a7a-928a-8928-bf5d9d8a8e50"}

Kelly