What mean error "Invalid association target" at saving data with SAPUI5?

[former_member612022]

Response text of error "Invalid association target" at saving data in the course (self-paces) Evolved Web Apps with SAPUI5 / Week 4 / Unit 1:

"\{\"error\":\{\"code\":\"SEPM_BO_COMMON/030\",\"message\":\{\"lang\":\"en\",\"value\":\"Invalid association target\"},\"innererror\":\{\"application\":\{\"component_id\":\"OPU-BSE-SDE\",\"service_namespace\":\"/IWBEP/\",\"service_id\":\"GWSAMPLE_BASIC\",\"service_version\":\"0001\"},\"transactionid\":\"B9E0A2A100BE0120E005D0954D304C95\",\"timestamp\":\"20190705102803.1820210\",\"Error_Resolution\":\{\"SAP_Transaction\":\"For backend administrators: run transaction /IWFND/ERROR_LOG on SAP Gateway hub system and search for entries with the timestamp above for more details\",\"SAP_Note\":\"See SAP Note 1797736 for error analysis (https://service.sap.com/sap/support/notes/1797736)\",\"Batch_SAP_Note\":\"See SAP Note 1869434 for details about working with $batch (https://service.sap.com/sap/support/notes/1869434)\"},\"errordetails\":[\{\"code\":\"SEPM_BO_COMMON/030\",\"message\":\"Invalid association target\",\"propertyref\":\"\",\"severity\":\"error\",\"target\":\"\"},\{\"code\":\"/IWBEP/CX_MGW_BUSI_EXCEPTION\",\"message\":\"Error occurred while processing the request\",\"propertyref\":\"\",\"severity\":\"error\",\"target\":\"\"}]}}}"