I keep getting this error when testing at core filing.org:

cvc-elt.1.a: Cannot find the declaration of element 'Invoice.

(The invoice document is complete with and tags. I believe something is wrong with my Schema document.

/Downloads/Schemalnvoice.xml 1 3 UBL Catalogue Schema Document -> 4 10 Y 11 12 xs:import namespace "UBLCommonBasicComponents 13 schemaLocation-"http://www.skipwhite.com/ag2018/UBLCommonBasicComponentsSchema.xsd"/> 14 15 16 17 18 19 20 exs: sequence> -Reference all child elements and 1st parent elements > 23 24 25 26 27 28 29 30 cxs:element ref-"cbc: ID" minoccurs-"1" max0ccurs-"1"/ os : element ref-"cbc :Name" minOccurs="1" max0ccurs="1"/> exs: element ref="cbc: IssueDate" minOccurs="1" maxOccurs="1"/> exs:element ref-"cbc:Note" minoccurs-"0" max0ccurs "unbounded"/> xs:element ref-"cac:ProviderParty" min0ccurs "1" max0ccurs "1"/> exs:element ref="cac : ReceiverParty" minOccurs="1.. max0ccurs="1> xs:element ref-"cac:CatalogueLine" minoccurs-"1" max0ccurs "unbounded"/> exs:element ref="cac: CatalogueLine" minOccurs="1" max0ccurs unbounded"/> /xs:sequence /xs:complexType 32/xs:element> 33/xs:schema