Error IW172 with SAP CJ20

We have a project in CJ20 and then we made a budget for that project. And we also made some more material in material planning but when trying to save, we received an error IW172.
"Error occurred during budget check, see cost protocol"
Diagnosis
An Error occurred during the budget availability check
Procedure
Display the cost determination log for the order or network plan for more detailed information on the error.
