Solution : https://service.sap.com/sap/support/notes/552289 (SAP Service marketplace login required)
Key words : 
work process -> dispatcher -> message server -> dispatcher -> enq work process, work process -> gateway -> gateway -> dialog process, enq work process, profile parameter enque/delay_max, enqu/table_size solution [1] question, system rejects lock requests, dialog work processes, application server sets, enq process, enque/table_size = 20000you
Related Notes : 
       
| 1552733 | CD: Lock table overflows when deleting | 
| 1423066 | Optimization of the performance in EWM | 
| 1118297 | XI runtime: QRFC processing of messages | 
| 923610 | Memory parameter recommendations for banking systems | 
| 852524 | Deletion of reservations from APO |