3644342 - Getting error "invalid main part" for Email output type when generating billing documents in SAP S/4HANA Cloud Public Edition

Error occurs as Invalid main part in email output channel when generating billing documents. 

SAP S/4 HANA Public Cloud 

1. Open the "Manage Billing Documents" app.
2. Select a billing document.
3. Trigger billing document output with type as email.
4. Error occurs as Invalid main part.

Missing or blank HTML/Text body in the email template YY1_BILLI****_****_TEMPLATE for form language like EN is causing the "Invalid main part" error when generating email output for billing documents.

1. Navigate to the "Maintain Email Templates" app.
2. Select the email template named "YY1_BILLI**_****_TEMPLATE".
3. For the form language like English , ensure that both the HTML Body and Text Body fields are populated with appropriate content.
4. Save the changes.
5. Retry generating the billing document with email output.

email output error, invalid main part, billing document, manage billing documents app, SAP S/4HANA Cloud Public Edition, maintain email templates, YY1_BILLING_EMAIL_TEMPLATE, HTML body blank, text body blank, email template error, output control billing. , KBA , SD-BIL-GF-OC-2CL , Output Control Billing (Public Cloud) , Problem