Since 2108CE items can`t add to a service entry sheet if the user does not have authorization to maintain a purchase order.
SAP S/4 HANA Cloud 2108
Wrongly an error will be raised and the item will not be added to a service entry sheet. Therefore the user need to have the authorization to maintain a purchase order (Business Catalog: SAP_MM_BC_PO_MANAGE_PC | Write, Read, Value Help: unrestricted).
A correction will be implemented on the next Hotfix Collection S4HANA CLOUD 2108 SPS 4. In the meantime, please extend the role to the affected users to allow them to maintain purchase orders. Add the Business Catalog SAP_MM_BC_PO_MANAGE_PC with no restrictions for ‘Write, Read, Value Help’ to the role of the affected users.
KBA , MM-PUR-SVC-SES , Service Entry Sheet for Service Procurement , Problem